Buyers guide to Rx-7s
04-14-2003, 11:53 PM
#1
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Join Date: Jan 2003
Location: Glenwood, NJ
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just in case the page goes down.... I copied it here... http://www.aaroncake.net/RX-7/buy1.htm and to buy a turbo II http://www.aaroncake.net/RX-7/buy2.htm
I take no credit. I just gotta say this is an awesome everything to konw on what to look for when you buy an FC and FCS!!!!!
So you want to buy an RX-7? Good! You'll be happy you did, as long as the car you get is in good shape. However, in order to pick the right car you must know what to look for. Don't count on a mechanic to know how to inspect the RX-7. Most are not versed in the rotary engine, and have no idea about the intricacies of these cars. A good inspection is easy to perform, though, even if you have only very basic mechanical skills.
This list covers the non-turbo (naturally aspirated, or "NA") second generation RX-7. If you are looking for a turbo, most of this stuff still applies, but there are additional steps to take. Please see How To Buy An '86-'91 Turbo RX-7 after reading this document for additional turbo related information.
The Body
The first thing you want to look at is the body. It's condition will tell you about the rest of the car. For example, if it is dirty and dull, you can assume that the previous owner did not take very much pride in his/her can and did therefore not give the body and paint the attention it deserved. Odds are you will find many other things wrong with such a car, so keep your guard up. If things look decent, you can make a more detailed inspection.
The Paint
The factory paint on the 2nd Gen. RX-7 is actually very good, and if cared for properly will still be in good shape. Look for peeling clear coat and paint, which can signal a cheap repaint. This may be due to standard wear or something like accident damage. Drips and runs should not exist, and will again be a signal of a cheap repaint. Odds are that cheap paint will become a problem in a few years when it starts to chip, flake and peel.
The Body
Look for the obvious first: big dents, dings, rust, etc. Dents and dings can be repaired fairly easily if they are small, but larger ones will be a hassle. Rust is bad, period. Realistically, all cars will acquire rust after a few years on the road, but it should not be excessive. Look under the car with a flashlight. There should not be any holes in the floor, sills, or frame rails (that are not factory). Such damage is expensive to repair as the interior must be removed so new panels can be welded in. Also look for bent frame or welding, which can be a signal of previous repairs. If the frame is bent or crushed, the car has been in an accident and it would be a good idea to get the alignment checked by a frame shop. Rust on RX-7s is common at the edged of the rear wheel wells, along the bottom of the doors and on the bottom of the front fenders. If possible, remove the front wheel well plastic guards and look toward the rear of the car. You will probably see some significant rust where the firewall meats the underside. It may even have rusted though. This is very common, but can probably be used as a bargaining chip. Check also to see if some sort of rust protection has been used over the yeas. If you look on the door sills, you will see several black rubber plugs. If these are new looking, you can assume that they have been replaced when the rust protection was applied as the old ones usually break.
Previous accident damage is a little harder to find. Look for discoloured or distorted areas, or places where things just don't quite match up. RX-7s have some subtle compound curves which are hard to replicate with body filler. You may be able to notice it where the trim attaches to the body as that area has a sharp curve the body fillers do not like. Don't immediately discount a car that has accident damage. If it was repaired correctly and wasn't too severe to begin with it should be OK. You might want to have a body shop look at it though. They will literally be able to tell by looking at it.
Rust behind the tail lights in the interior is common due to leaking gaskets, but it certainly should not be rusted though.
Doors/Locks/Hatch
A common failure on RX-7s is the drivers door lock. There are several failure modes, but most of them result in the driver being locked out of the car. Look for evidence of forceful entry, such as damaged window seals. If the handle or lock was replaced and not rekeyed, you will have a different key for the drivers door and for the ignition. Not really a problem, but very annoying in a car that is supposed to be one-key. Needless to say, all locks and handles should work properly. In some cars, there is a hatch release under the drivers seat. It should work, as should the fuel door release right beside it. If they don't, the cable my be broken. This is annoying to replace, and it is even more annoying to have to pry the fuel door open with your key. The rear hatch glass is heavy, so make sure the gas struts are in good working order. The hatch should spring up when released, and stay up on it's own when opened fully.
Windows
The manual windows are very reliable. The electric windows do a have a few quirks. If they move up slowly and/or need assistance, the tracks probably need to be cleaned and regreased. If they don't work at all, suspect the switches. The motors rarely go bad. Electrical problems will be discussed in their own section.
The Engine
Once you are sure the body is in good shape, you can move onto the engine. Contrary to popular belief, the rotary is a very reliable engine if cared for properly. This is of course true of any engine, but the rotary is more sensitive to poor maintenance. Most mechanics (even Mazda mechanics) don't know what they are doing, so it is up to you to make the decisions. There are some fairly simple checks that can be done, and they will be a very good indication on the condition of the engine.
Engine Bay
Take a quick look at the engine bay. There shouldn't be anything obviously wrong. No severe rust (although rust is common on the alternator, air pump, exhaust, under the break and clutch master cylinders and near the cold start assist tank), fluid leaks or frayed wires. You may spot some oil leaking from under the oil filter. This is the oil pressure sender and leaks around that area are common. Check the belts to see if they are brittle or frayed. Also look at the condition of the hoses to make sure they are not cracked or broken. The idea here is to just get a general idea on the condition of things.
Compression
The next most important thing to check is compression. This will give you an idea of the current internal condition of the engine, but cannot predict future events. The best way to have compression checked is to find a Mazda dealer with the special tester. A standard compression gauge will work, but can be inaccurate if uses improperly. Good compression is a 7 or higher on the Mazda tester, and higher than 85 PSI on a standard gauge. Do two tests, one with the engine cold and one with the engine warm.
Starting/Warm Up
Get there first thing in the morning and start the engine. This guarantees a cold start. It should immediately rev to around 3000 RPM for about 20 seconds, then drop to 1500 RPM, and then slowly come to a solid 750RPM idle after it has warmed up (about 5 minutes). The idle should be smooth, not rough and surging. Applying the brake should not bring down the idle, nor should turning on the A/C. If it does, the BAC valve may be defective or sticking. After the car has fully warmed up, shut it off, wait 15 minutes (look at some other part of the car) and then try to restart it. If it doesn't fire right up it may be flooded. This is a standard problem, but a pain to fix as the usual cause is leaking fuel injectors. Use this as a bargaining chip to bring the price of the car down a few hundred dollars. If you do the fix yourself, you should spend just about that much.
While the car is warming up, you may want to remove the rad cap and take a look. The coolant level should be pretty close to the top. Also, there should be no bubbles seen. If you see a steady stream of bubbles coming from somewhere else in the system, and it increases as the RPM of the engine does, there is an internal coolant leak. Avoid the car unless you plan on rebuilding the engine soon.
Needless to say, if the "Check Engine" light comes on, there is a problem somewhere.
Oil Consumption
Rotary engines are designed to burn oil. A small amount of oil is injected during intake, which helps to lubricate the apex seals and allow the engine to build compression. Ask the seller about the oil consumption history. If he or she proudly states that the car never burns any oil, they are either lying or there is a serious problem with the metering oil pump, the lines or the oil injectors. Either way, I would look very suspiciously at the car from now on. There are procedures for testing the metering oil pump and related hardware, but they are beyond the capacity of the standard inspection. In this case, you can only guess at the condition of the engine. Finding oil containers in the car is a good sign and proves that the seller is just lying to try to make a sale. If the engine has chronically low compression and floods easily the oil injection system may have been malfunctioning for a long time. For the record, mechanical '86-88 metering oil pumps are more reliable then the electronic '89-91 pumps. Suspect a failure in the metering oil system if the rear rotor has low compression but the front is fine. Normal oil consumption for these cars is about 1 quart per 1000 miles, but this will vary depending on how spirited your driving is.
Smoking
It is normal for a rotary engine to let out a few puffs of oil smoke (grey, dark blue) when it is started. This is due to the side oil seals staying in one position and allowing oil to seep past. It isn't anything to really worry about, as long as it does not continue for more than a few seconds. If it does, suspect almost total failure of the side seals. You will use much more oil than normal, and end up trailing huge clouds of smoke behind you. Spark plugs will also foul quickly. On the plus side, smoking engines are a great candidate for a rebuild and most likely the excess oil entering the rotor chambers over the years has prevented extreme wear on the apex seals and housings.
If the engine is hard to start, stumbles and then billows out huge clouds of white smoke, there is a serious problem. Most likely this condition will also be accompanied by mysterious coolant loss and possible overheating. The reason is that the O rings around the housings have failed, thus allowing coolant to enter the combustion chamber. This is very bad, and I would avoid the car unless you want to rebuild the engine.
Black or very dark blue smoke is usually excess fuel. The most common cause of this is leaking injectors.
Once the engine has warmed up, hold it at about 6K for 30 seconds then let off the throttle quickly. If you (or someone else) can see smoke coming from the exhaust, the oil seals are probably on their way out.
Overheating/Temperature
If the car has been overheated in the past, or overheats when you are looking at it, just walk away. Overheating is instant death for a rotary engine and is not tolerated even once. For '86-88 cars, normal operating temperature is about 1/4 way up the gauge. For '89-91 cars it is about half way. Both gauges will be very slightly higher if the A/C is on.
Pulsation Damper
If the car is an '86-88, look at the front of the primary fuel rail. This is where the pulsation damper sits. On the '86-88 cars, these have a tendency to leak, thus spraying gas onto the exhaust manifold. This causes an engine fire which is very difficult to put out because of the flow of fuel. If it is leaking, don't drive he car, and have it replaced immediately. '89-91 cars don't have this problem as the damper is integral to the fuel rail.
5th and 6th Ports
All non turbo 13B engines used in the 2nd generation RX-7 have a 6 port induction system. The 5th and 6th ports remain closed below about 3500 RPM, preserving air velocity and thus low end torque. After that, the ports open up and improve top end horsepower. When the ports open up, the gain is roughly 25HP. If the ports are not working properly, you will loose quite a bit of top end punch. To test them, first locate the actuators. They are located on top of the ACV valve above the exhaust manifold. Looking from the passenger side of the engine compartment towards the drivers side, you will see two cylinders with rods sticking out from them. Those are the actuators. Smear some grease on the shafts and after your test drive look to see if the grease has moved. If it has, then the actuators are working. If not, something needs to be repaired. If the car was not driven at high RPM, then most likely the actuators have frozen from age. Removing them and applying penetrating lube usually brings them back to life. If the actual port valves are stuck, the intake manifold probably has to come off.
Interior
The newest second generation RX-7 is already more than 10 years old, so wear in the interior is to be expected. However, there are a few RX-7 issues you should look for.
Carpet
The carpets should be relatively clean, and there should be a mat under the passenger and driver's feat. There should be no weird stains on the floor, as those may signal rust problems below. If you see a lot of salt build up behind the seats, expect rust problems. Water tends to collect back there. Maroon interiors have a tendency to discolour, turning a shade of green if left in the sun. For the most part, the other colours are trouble free. Of course, you want to check the carpet for rips, holes, etc.
Seats
Wear is normal on the seats, as they are often used when driving the car. If the seat is cloth, look for discolouration, ripping, stains, etc. If they are leather, look for cracking and cheap repairs. The seats sit on adjustable tracks so it is a good idea to have a look at them too. They should easily move and not stick. You will probably notice the seat retaining bolts have rusted. This is normal, as long as they haven't rusted through. If they have, repairs will be necessary as the car is not safe to drive with loose seats.
Trim
'86-8 trim is quite brittle and has a tendency to crack. Don't be surprised if the radio surround is broke at the top, the clock/idiot light trim is cracked, the vents on the dash near the doors are loose/missing/cracked and the vents under the windshield are cracked. This is normal in any older car, but much more so in the RX-7. Also, check the steering column cover. It is subject to a to a lot of abuse which tends to destroy the screw holes. For the most part, '89-91 trim is a lot more forgiving and just plain higher quality. Remember that the price of small trim pieces can quickly add up. If replacing trim, you might as well use the '89-91 part.
Automatic Seatbelts
If the car is equipped with automatic seatbelts, check to see if the recall has been done. If the owner has receipts, then it is easy. Otherwise you will have to take the VIN number to a Mazda dealer and find out if it has been done. If the seatbelts are broken, don't worry as they are under lifetime warranty by Mazda. The current owner may not know this though and it may be a bargaining chip.
Headliners/Mirrors
The headliners on these cars are basically trouble free. However, the flip down mirror can become very loose in it's holder. There is a small plastic sphere that will crack over time. This is very annoying as it causes the visors/mirrors to hang down in you or your passenger's field of view.
Sunroof
If the car is equipped with a sunroof, then make sure it moves freely. It if sticks, chances are it has to be removed, cleaned and regreased. The tracks will build up crud after 10+ years in the weather.
Electrical
Here we come to one of the more involved sections, with some of the more potentially irritating problems. Unfortunately, the 2nd generation RX-7 just doesn't have a very good electrical system. '86-88 cars are a little worse then the later cars, but both can have their share of problems. Some are simple to fix, some are expensive. You will have to make the call as to whether a problem is big enough to consider looking at another car. However, odds are that the other will have a few issues itself. Most problems can be traced to bad soldering and/or faulty grounds, but some are just bad design.
Headlight Switch/Wiring Harness
By far the most common failure in the RX-7 is the headlight switch and it's associated wiring harness. The basic sequence of events is that the headlight switch dies due to cold solder joints, which then generates excess heat, which then melts the connector and wiring harness. The problem can be repaired by replacing the faulty switch and wiring harness, but with just the switch priced at around $300 this gets expensive fast. Most of the time switches can be found at the wreckers for around $5 though. And the old switch can always be rebuilt if it didn't take it's connector and wiring harness with it when it died. A rebuilt switch, if done properly, is very reliable. To test the switch, just turn on the headlights, try the headlight cleaning switch (just raises the lights without turning them on), and test the defroster switch. If any of them doesn't work, then suspect the switch. If the dash backlighting, headlights or marker lights don't come on then odds are the headlight switch is bad.
Turn Signal Lever/High Beam Switch
These switches are subject to the same type of failure as the headlight switch, but do not damage the wiring harness when they die. Replacement costs about the same.
Wiper/Hazard Switch
This switch will fail as the headlight switch will, but will not damage the harness. Symptoms of it failing are non-working intermittent wipers, non-working hazard lights, wipers that don't park, and of course non operational wipers. Replacement is about the same as the headlight switch. If the car is not equipped with a rear wiper, there will be an extra switch that apparently does nothing. Tell your friends it engages secret engine modifications.
Cruise Control Switch
The cruise switch is trouble free.
CPU
The CPU is located behind the drivers kick panel, hidden by a wiring loom. It controls such things as the turn signals, horn, warning beep, etc. Over time, the poor Mazda solder joints will begin to become intermittent which will result in the malfunctioning of the aforementioned devices. The usual fix is to open up the CPU and resolder all the big joints. This is not an expensive or difficult task to do yourself, but a dealer will want to replace the whole CPU. I don't even want to know what that would cost
Emissions Control Unit (ECU)
The ECU is the real brains of the car, coordinating everything from spark timing to fuel delivery to idiot light functions. Unfortunately, this device is subject to two types of electrical malfunction. The first is bad solder joints. Go figure, eh? The second is bad grounding. As the car ages, the ground connections dirty up and corrode. This makes them intermittent and high resistance. The effect on the ECU from both these conditions is erratic operation, which can cause all manner of engine related problems. Perhaps one of the most common is the infamous 3800RPM hesitation. Coming up to 3800RPM, the engine may hesitate horribly. This is usually related to ECU problems. Cold solder joints can be repaired by resoldering the ECU and the grounding problem can be fixed by regrounding. A dealer may want to replace the whole unit though, and this would be at great cost.
Dead Horns
See "CPU"
Heater/AC/Fan Controls
The device that controls the heater, A/C and fan is referred to as the logicon. It is subject to the same soldering problem as most other parts in the car. Failures in the logicon show up in several ways. You may not be able to adjust the fan speed, adjust the air mix or change the air outlet locations. There are also several motors that control the flow of air. The one you want to be concerned with is the air mix motor. It controls the ratio of unheated/cooled air to heated/cooled air. If the logicon has fried, it may take the motor with it. If the motor has fried, it may take the logicon with in. You can repair the logicon yourself by resoldering the joints, but beware of price if you take it to a dealer. They will probably want close to $400 for a new one and it will be subject to the same types of failures as the old.
Stereo
For the most part, the stereo is trouble free. If it does fail, it will be due to bad soldering. The most common symptom is intermittent sound from one or more speakers, failed displays or inoperative controls. The radio can be repaired, but if it is removed you might as well install a good aftermarket unit. This will probably cost less then replacing it with another Mazda unit.
Power Antenna
As with most other power antennas, the unit on the RX-7 takes a lot of abuse and will wear out over time. If the motors runs (which you can hear in the rear drivers side) but the antenna doesn't move, the small plastic push strip has broken of come off the gears. It can usually be repaired with a minimum of fuss. Don't expect to find a good power antenna at the wreckers. If the motor does not run, first check the fuse. It may have been removed to keep the antenna from freezing up in the winter. If the radio is aftermarket and the antenna doesn't work, chances are that the relay required for the ground activated antenna (opposite of normal) was not installed. Oh, and regardless if the antenna is working or not, these cars get horrible radio reception.
Power Windows
Over time, the power window switches will tend to build up a carbon coating on the contacts. This usually leads to less than ideal window operation. The fix is to replace the switch, or use fine sandpaper to clean the contacts in the old ones. Personally, I would replace rather then repair as the sand paper will take the nickel coating off of the contacts.
Transmission/Drivetrain/Suspension/Brakes
With a few minor problems, these components of the car are reliable and trouble free. As long as the car has been cared for you shouldn't find any problems in this area.
Shifter
Don't be too surprised if the shifter is sloppy. The shifter bushings in these cars will fail over time and need to be replaced. The job is not complicated or expensive and is easily done in an hour. Don't worry to much about it.
Transmission
It goes without saying that the transmission should shift smoothly and easily. However, it will feel a little more notchie than other cars. Also, the 2nd gear syncro may be worn out, resulting in a grind when shifting quickly into second. The only way to fix this is to replace or rebuild the transmission. This is a common problem in the 2nd generation RX-7, so don't count on another car's transmission to be perfect either. Another common problem is noise. If the bearings are worn (mostly due to old or no transmission oil) they will provide a constant whine while the car or transmission is in motion. The only cure for this is a transmission rebuild or replacement, which is expensive. Note that the transmission may last for many more miles with this condition, or it could die next week. To check the level of transmission fluid, jack the car up so that it is raised and level. Now remove the fill plug from the drivers side front of the transmission (right near the starter). Stick in your pinky finger. You should be able to feel the fluid level. If you cannot feel it, the fluid is low and there is a leak somewhere.
Clutch
Make sure the clutch is not excessively worn (slipping) by shifting into a higher gear and then getting on the gas. The RPMs should rise as the car's speed increases. If the speed of the engine spikes but the car accelerates slowly then it is a good indication the clutch is slipping.
Driveshaft
As with any older car, the u-joints on the driveshaft are probably near or already past their useful life. This will show up as a very noticeable vibration when the car is moving. The problem here is that the stock Mazda driveshaft does not have replaceable joints, so you need a whole new driveshaft. However, do not buy the Mazda shaft if you can help it. Get an aftermarket shaft with replaceable joints to avoid this whole problem again.
Suspension
Listen for bumps, thumps and other things. No side of the car should sag, and it should not bounce up and down when you push on it. Excessive nose-dive while braking is bad, as is squatting when accelerating. You may notice some negative camber in the rear wheels. Toe in may also be present. Most RX-7s have a little negative camber so I wouldn't put too much worry into it. The toe in is due to the Dynamic Tracking Suspension System, and will straighten out when the car begins to move. The shocks should not leak oil, and the springs should not sag.
On cars so equipped, the AAS (Auto Adjusting Suspension) will probably not work. The system didn't do much anyway. If it doesn't work, odds are it has been disconnected, the struts have been replaced with standard struts (good) or the 10+ year old suspension is just worn out. The system was just a gimmick anyway, and a true sports car does not need such frivilties.
Steering
The car should track straight and no strange sounds should he hear when turning the wheel. If such sounds are heard, the ball joints and/or tie rod ends are probably worn out. They will need to be replaced and the car will have to be aligned.
Brakes
Needless to say, the brakes should work. They should feel fairly firm, and not drop straight to the floor. No pulsing should be felt. If it is, one of more rotors are warped. The brake lights should come on when the brakes are applied, and the parking brake should firmly hold the car on a hill. Applying the parking brake should also light the "BRAKE" idiot light. On application of the brakes the car should not pull to one side. If the car is equipped with ABS, find a deserted wet spot and slam on the brakes. The ABS should kick in. Also check the fluid. Black brake fluid signals neglect, or a history of cheap brake jobs. Be wary of such a car as there are probably hidden brake problems.
Tire Wear
The tires should not show any weird wear patterns. Most likely, the rears will be worn more than the fronts. This is normal for a RWD car as most people don't rotate their tires.
Bearings
Jack up each end of the car and try to rip the wheel off with your hands. You shouldn't feel any play or hear any clicking. If you do, the bearings or races are probably worn. One note about the front wheels: the bearing and hub are integral. That is, if one is bad you have to replace the whole assembly. This is expensive. Remember that bearings are a wear item on all cars and will need to be replaced/repacked at some point. Ask when this was last done.
There, I think that's just about it. Don't take this list to mean that the RX-7 is not a reliable car. For the most part, any used car will have a similar list of quirks. Hell, any new car will have the same thing. Remember the airbag computer failures on the 2001 Impala? Good luck in your search, and happy rotoring.
Turbo II
This document is the companion to How To Buy An '86-'91 Non-Turbo RX-7. The non-turbo document contains all the buying information common to both models of RX-7s. This document contains the turbo specific information. It is very important that you read both to get the full picture. It is best to read the non-turbo information first, then head back here to get the turbo specific stuff.
For the most part, the turbo RX-7 is very similar to the non-turbo, with some suspension, drivetrain, braking and of course engine changes. These differences are covered below.
The Engine
It is hard to make a judgement on the "average" life of a turbo rotary since it is very dependant on the care it has received. Nevertheless, the normal guess at average life is around 100,000 miles, but I have seen engines that were still nearly prefect with over 175K on them, as well as engines that were blown at 50K.
Compression
Checking the compression in a turbo rotary is very important. The engine is under much greater stresses when pressurized, which therefore relates to more wear and shorter engine life. Be especially careful if the car is modified, as boost increases will put even more strain on the engine. Look for an upgraded fuel system. Once the boost is increased past a few PSI, extra fuel will be required to prevent deadly detonation.
Oil Consumption
Oil consumption is very slightly higher on turbo cars, but it is hardly noticeable.
Smoking
Aside from smoking caused by worn seals that both the NA and turbo models can suffer from, smoking can also be caused by poor seals in the turbo. If the compressor seal is bad, oil will bypass into the intake tract and be burned by the engine. This is easy to spot since the car will smoke during long periods of deceleration as the engine vacuum will draws oil past the seal. Excessive amounts of oil will also be present in the intercooler and piping. If the turbine (exhaust side) seal is bad, there will be a constant flow of smoke from the exhaust, which will increase greatly when the car is driven under boost. If you can remove the precat/downpipe from the rear of the turbo, you will most likely find oil inside.
Any smoke coming from the turbo will be blue.
Overheating/Temperature
The turbo cars do run slightly hotter than the non turbo cars.
5th and 6th Ports
Turbo cars don't have them.
The Turbo (and related)
The turbo is of course the fun part of the Turbo II. There is nothing spectacular about the turbo system in the TII, save for the twin scroll system employed in the '86-'88 cars. Therefore, a few simple checks will help determine the condition of the turbocharger and related components. Note that the turbo is located at passenger side of the engine between the frame rail and the engine itself.
Turbocharger Heat Shields
Check to make sure the metal heat shields are in place over the turbine (exhaust) section of the turbo. These shields make a large difference in underhood temperature since the turbo is a massive source of heat.
Turbocharger Oil and Water Lines
Inspect the turbocharger externally and check for oil and water leaks. This may be difficult if the stock heat shields are still in place. Also check the lines where they meet the engine. Repairing any leak is normally straightforward, but it may not be so straightforward to actually get to the leaking part (normally a gasket) depending on which line is causing the leak.
Cracking
The turbos have a habit of cracking on the turbine side. Normally this happens internally and therefore the cracks are not visible on the outside. However, if you see cracking on the outside (specifically on the flange where it meets the manifold) then it is a sign of severe cracking, which will normally mean replacement of the turbine housing. This gets expensive. The same goes for the manifold. Large cracks in the exhaust manifold will mean replacement, which involves pulling the turbo. Lots of labour for someone who has not done it before.
Turbine Shaft Play
Remove the black plastic air duct that goes into the turbo (the turbo inlet duct, or "TID"). Now, with your fingers, give the compressor a spin. It should spin fairly freely and smoothly. There will be some dragging since the bearing will be stiff without it's oil jacket (only present with the car running), but it should be smooth throughout it's rotation. Now, alternately push and pull on the shaft. It should not move. If it does, you are looking at severe bearing and shaft wear, meaning replacement or a rebuild of the turbo. Very expensive. Apply pressure on the shaft, trying to push it left and right. Some play is normal, but it should not be excessive (compressor should not contact the housing). This play is caused by slack in the bearing, which is taken up when the oil film forms and the shaft "floats" on it's fluid bearing. While you're there, look for excessive oil in the compressor housing. Some is normal, but large amounts mean a turbo rebuild.
Twin Scroll
The '86-'88 TIIs employ a system called "twin scroll" to help combat turbo lag. Basically, at low RPMs, a flapper door inside the manifold closes and shuts off one of the two exhaust paths to the turbine. This causes the first path to direct exhaust gasses to hit the turbine wheel at a very sharp angle, thus quickly spooling the turbo. As the engine speed (and thus exhaust gas flow) increases, the flapper door is opened to allow the second exhaust passage to flow, thus allowing the turbo to flow to it's full potential.
This system relies on a solenoid, flapper door and actuator. Unfortunately, there is no easy way to test it. Jacking up the car and manually pressing on the actuator (front of the turbocharger, big silver can) will verify the assembly moves, but will not tell you if it works properly when the car is running. Fortunately, the twin scroll system is pretty reliable and failures are uncommon.
The twin scroll system was removed on '89+ cars due to better turbo design.
Intercooler and Piping
The intercooler (located on top of the engine) should be free of large dents. There should be no holes, and the fins should be straight and not filled with crud. A dirty intercooler is easy to clean, but one that has most of it's fins bent will be very ineffective and will need to be repaired or replaced.
The piping to and from the intercooler should be in good shape, with no holes or large dents. Carefully inspect the rubber hoses and check for cracks. It is common to find large cracks which will show up as a boost leak (low boost when driving, loud hissing noise). They are fairly inexpensive to replace.
Boost Pressure
If you have an aftermarket boost gauge available, check the boost pressure. The boost on a stock car should read 6.2 PSI. If the car modified, expect more boost. The pressure you see will depend on the modifications. Low boost can have many causes, from a clogged air filter to a dead turbo. Keep this in mind.
So you want to buy an RX-7? Good! You'll be happy you did, as long as the car you get is in good shape. However, in order to pick the right car you must know what to look for. Don't count on a mechanic to know how to inspect the RX-7. Most are not versed in the rotary engine, and have no idea about the intricacies of these cars. A good inspection is easy to perform, though, even if you have only very basic mechanical skills.
This list covers the non-turbo (naturally aspirated, or "NA") second generation RX-7. If you are looking for a turbo, most of this stuff still applies, but there are additional steps to take. Please see How To Buy An '86-'91 Turbo RX-7 after reading this document for additional turbo related information.
The Body
The first thing you want to look at is the body. It's condition will tell you about the rest of the car. For example, if it is dirty and dull, you can assume that the previous owner did not take very much pride in his/her can and did therefore not give the body and paint the attention it deserved. Odds are you will find many other things wrong with such a car, so keep your guard up. If things look decent, you can make a more detailed inspection.
The Paint
The factory paint on the 2nd Gen. RX-7 is actually very good, and if cared for properly will still be in good shape. Look for peeling clear coat and paint, which can signal a cheap repaint. This may be due to standard wear or something like accident damage. Drips and runs should not exist, and will again be a signal of a cheap repaint. Odds are that cheap paint will become a problem in a few years when it starts to chip, flake and peel.
The Body
Look for the obvious first: big dents, dings, rust, etc. Dents and dings can be repaired fairly easily if they are small, but larger ones will be a hassle. Rust is bad, period. Realistically, all cars will acquire rust after a few years on the road, but it should not be excessive. Look under the car with a flashlight. There should not be any holes in the floor, sills, or frame rails (that are not factory). Such damage is expensive to repair as the interior must be removed so new panels can be welded in. Also look for bent frame or welding, which can be a signal of previous repairs. If the frame is bent or crushed, the car has been in an accident and it would be a good idea to get the alignment checked by a frame shop. Rust on RX-7s is common at the edged of the rear wheel wells, along the bottom of the doors and on the bottom of the front fenders. If possible, remove the front wheel well plastic guards and look toward the rear of the car. You will probably see some significant rust where the firewall meats the underside. It may even have rusted though. This is very common, but can probably be used as a bargaining chip. Check also to see if some sort of rust protection has been used over the yeas. If you look on the door sills, you will see several black rubber plugs. If these are new looking, you can assume that they have been replaced when the rust protection was applied as the old ones usually break.
Previous accident damage is a little harder to find. Look for discoloured or distorted areas, or places where things just don't quite match up. RX-7s have some subtle compound curves which are hard to replicate with body filler. You may be able to notice it where the trim attaches to the body as that area has a sharp curve the body fillers do not like. Don't immediately discount a car that has accident damage. If it was repaired correctly and wasn't too severe to begin with it should be OK. You might want to have a body shop look at it though. They will literally be able to tell by looking at it.
Rust behind the tail lights in the interior is common due to leaking gaskets, but it certainly should not be rusted though.
Doors/Locks/Hatch
A common failure on RX-7s is the drivers door lock. There are several failure modes, but most of them result in the driver being locked out of the car. Look for evidence of forceful entry, such as damaged window seals. If the handle or lock was replaced and not rekeyed, you will have a different key for the drivers door and for the ignition. Not really a problem, but very annoying in a car that is supposed to be one-key. Needless to say, all locks and handles should work properly. In some cars, there is a hatch release under the drivers seat. It should work, as should the fuel door release right beside it. If they don't, the cable my be broken. This is annoying to replace, and it is even more annoying to have to pry the fuel door open with your key. The rear hatch glass is heavy, so make sure the gas struts are in good working order. The hatch should spring up when released, and stay up on it's own when opened fully.
Windows
The manual windows are very reliable. The electric windows do a have a few quirks. If they move up slowly and/or need assistance, the tracks probably need to be cleaned and regreased. If they don't work at all, suspect the switches. The motors rarely go bad. Electrical problems will be discussed in their own section.
The Engine
Once you are sure the body is in good shape, you can move onto the engine. Contrary to popular belief, the rotary is a very reliable engine if cared for properly. This is of course true of any engine, but the rotary is more sensitive to poor maintenance. Most mechanics (even Mazda mechanics) don't know what they are doing, so it is up to you to make the decisions. There are some fairly simple checks that can be done, and they will be a very good indication on the condition of the engine.
Engine Bay
Take a quick look at the engine bay. There shouldn't be anything obviously wrong. No severe rust (although rust is common on the alternator, air pump, exhaust, under the break and clutch master cylinders and near the cold start assist tank), fluid leaks or frayed wires. You may spot some oil leaking from under the oil filter. This is the oil pressure sender and leaks around that area are common. Check the belts to see if they are brittle or frayed. Also look at the condition of the hoses to make sure they are not cracked or broken. The idea here is to just get a general idea on the condition of things.
Compression
The next most important thing to check is compression. This will give you an idea of the current internal condition of the engine, but cannot predict future events. The best way to have compression checked is to find a Mazda dealer with the special tester. A standard compression gauge will work, but can be inaccurate if uses improperly. Good compression is a 7 or higher on the Mazda tester, and higher than 85 PSI on a standard gauge. Do two tests, one with the engine cold and one with the engine warm.
Starting/Warm Up
Get there first thing in the morning and start the engine. This guarantees a cold start. It should immediately rev to around 3000 RPM for about 20 seconds, then drop to 1500 RPM, and then slowly come to a solid 750RPM idle after it has warmed up (about 5 minutes). The idle should be smooth, not rough and surging. Applying the brake should not bring down the idle, nor should turning on the A/C. If it does, the BAC valve may be defective or sticking. After the car has fully warmed up, shut it off, wait 15 minutes (look at some other part of the car) and then try to restart it. If it doesn't fire right up it may be flooded. This is a standard problem, but a pain to fix as the usual cause is leaking fuel injectors. Use this as a bargaining chip to bring the price of the car down a few hundred dollars. If you do the fix yourself, you should spend just about that much.
While the car is warming up, you may want to remove the rad cap and take a look. The coolant level should be pretty close to the top. Also, there should be no bubbles seen. If you see a steady stream of bubbles coming from somewhere else in the system, and it increases as the RPM of the engine does, there is an internal coolant leak. Avoid the car unless you plan on rebuilding the engine soon.
Needless to say, if the "Check Engine" light comes on, there is a problem somewhere.
Oil Consumption
Rotary engines are designed to burn oil. A small amount of oil is injected during intake, which helps to lubricate the apex seals and allow the engine to build compression. Ask the seller about the oil consumption history. If he or she proudly states that the car never burns any oil, they are either lying or there is a serious problem with the metering oil pump, the lines or the oil injectors. Either way, I would look very suspiciously at the car from now on. There are procedures for testing the metering oil pump and related hardware, but they are beyond the capacity of the standard inspection. In this case, you can only guess at the condition of the engine. Finding oil containers in the car is a good sign and proves that the seller is just lying to try to make a sale. If the engine has chronically low compression and floods easily the oil injection system may have been malfunctioning for a long time. For the record, mechanical '86-88 metering oil pumps are more reliable then the electronic '89-91 pumps. Suspect a failure in the metering oil system if the rear rotor has low compression but the front is fine. Normal oil consumption for these cars is about 1 quart per 1000 miles, but this will vary depending on how spirited your driving is.
Smoking
It is normal for a rotary engine to let out a few puffs of oil smoke (grey, dark blue) when it is started. This is due to the side oil seals staying in one position and allowing oil to seep past. It isn't anything to really worry about, as long as it does not continue for more than a few seconds. If it does, suspect almost total failure of the side seals. You will use much more oil than normal, and end up trailing huge clouds of smoke behind you. Spark plugs will also foul quickly. On the plus side, smoking engines are a great candidate for a rebuild and most likely the excess oil entering the rotor chambers over the years has prevented extreme wear on the apex seals and housings.
If the engine is hard to start, stumbles and then billows out huge clouds of white smoke, there is a serious problem. Most likely this condition will also be accompanied by mysterious coolant loss and possible overheating. The reason is that the O rings around the housings have failed, thus allowing coolant to enter the combustion chamber. This is very bad, and I would avoid the car unless you want to rebuild the engine.
Black or very dark blue smoke is usually excess fuel. The most common cause of this is leaking injectors.
Once the engine has warmed up, hold it at about 6K for 30 seconds then let off the throttle quickly. If you (or someone else) can see smoke coming from the exhaust, the oil seals are probably on their way out.
Overheating/Temperature
If the car has been overheated in the past, or overheats when you are looking at it, just walk away. Overheating is instant death for a rotary engine and is not tolerated even once. For '86-88 cars, normal operating temperature is about 1/4 way up the gauge. For '89-91 cars it is about half way. Both gauges will be very slightly higher if the A/C is on.
Pulsation Damper
If the car is an '86-88, look at the front of the primary fuel rail. This is where the pulsation damper sits. On the '86-88 cars, these have a tendency to leak, thus spraying gas onto the exhaust manifold. This causes an engine fire which is very difficult to put out because of the flow of fuel. If it is leaking, don't drive he car, and have it replaced immediately. '89-91 cars don't have this problem as the damper is integral to the fuel rail.
5th and 6th Ports
All non turbo 13B engines used in the 2nd generation RX-7 have a 6 port induction system. The 5th and 6th ports remain closed below about 3500 RPM, preserving air velocity and thus low end torque. After that, the ports open up and improve top end horsepower. When the ports open up, the gain is roughly 25HP. If the ports are not working properly, you will loose quite a bit of top end punch. To test them, first locate the actuators. They are located on top of the ACV valve above the exhaust manifold. Looking from the passenger side of the engine compartment towards the drivers side, you will see two cylinders with rods sticking out from them. Those are the actuators. Smear some grease on the shafts and after your test drive look to see if the grease has moved. If it has, then the actuators are working. If not, something needs to be repaired. If the car was not driven at high RPM, then most likely the actuators have frozen from age. Removing them and applying penetrating lube usually brings them back to life. If the actual port valves are stuck, the intake manifold probably has to come off.
Interior
The newest second generation RX-7 is already more than 10 years old, so wear in the interior is to be expected. However, there are a few RX-7 issues you should look for.
Carpet
The carpets should be relatively clean, and there should be a mat under the passenger and driver's feat. There should be no weird stains on the floor, as those may signal rust problems below. If you see a lot of salt build up behind the seats, expect rust problems. Water tends to collect back there. Maroon interiors have a tendency to discolour, turning a shade of green if left in the sun. For the most part, the other colours are trouble free. Of course, you want to check the carpet for rips, holes, etc.
Seats
Wear is normal on the seats, as they are often used when driving the car. If the seat is cloth, look for discolouration, ripping, stains, etc. If they are leather, look for cracking and cheap repairs. The seats sit on adjustable tracks so it is a good idea to have a look at them too. They should easily move and not stick. You will probably notice the seat retaining bolts have rusted. This is normal, as long as they haven't rusted through. If they have, repairs will be necessary as the car is not safe to drive with loose seats.
Trim
'86-8 trim is quite brittle and has a tendency to crack. Don't be surprised if the radio surround is broke at the top, the clock/idiot light trim is cracked, the vents on the dash near the doors are loose/missing/cracked and the vents under the windshield are cracked. This is normal in any older car, but much more so in the RX-7. Also, check the steering column cover. It is subject to a to a lot of abuse which tends to destroy the screw holes. For the most part, '89-91 trim is a lot more forgiving and just plain higher quality. Remember that the price of small trim pieces can quickly add up. If replacing trim, you might as well use the '89-91 part.
Automatic Seatbelts
If the car is equipped with automatic seatbelts, check to see if the recall has been done. If the owner has receipts, then it is easy. Otherwise you will have to take the VIN number to a Mazda dealer and find out if it has been done. If the seatbelts are broken, don't worry as they are under lifetime warranty by Mazda. The current owner may not know this though and it may be a bargaining chip.
Headliners/Mirrors
The headliners on these cars are basically trouble free. However, the flip down mirror can become very loose in it's holder. There is a small plastic sphere that will crack over time. This is very annoying as it causes the visors/mirrors to hang down in you or your passenger's field of view.
Sunroof
If the car is equipped with a sunroof, then make sure it moves freely. It if sticks, chances are it has to be removed, cleaned and regreased. The tracks will build up crud after 10+ years in the weather.
Electrical
Here we come to one of the more involved sections, with some of the more potentially irritating problems. Unfortunately, the 2nd generation RX-7 just doesn't have a very good electrical system. '86-88 cars are a little worse then the later cars, but both can have their share of problems. Some are simple to fix, some are expensive. You will have to make the call as to whether a problem is big enough to consider looking at another car. However, odds are that the other will have a few issues itself. Most problems can be traced to bad soldering and/or faulty grounds, but some are just bad design.
Headlight Switch/Wiring Harness
By far the most common failure in the RX-7 is the headlight switch and it's associated wiring harness. The basic sequence of events is that the headlight switch dies due to cold solder joints, which then generates excess heat, which then melts the connector and wiring harness. The problem can be repaired by replacing the faulty switch and wiring harness, but with just the switch priced at around $300 this gets expensive fast. Most of the time switches can be found at the wreckers for around $5 though. And the old switch can always be rebuilt if it didn't take it's connector and wiring harness with it when it died. A rebuilt switch, if done properly, is very reliable. To test the switch, just turn on the headlights, try the headlight cleaning switch (just raises the lights without turning them on), and test the defroster switch. If any of them doesn't work, then suspect the switch. If the dash backlighting, headlights or marker lights don't come on then odds are the headlight switch is bad.
Turn Signal Lever/High Beam Switch
These switches are subject to the same type of failure as the headlight switch, but do not damage the wiring harness when they die. Replacement costs about the same.
Wiper/Hazard Switch
This switch will fail as the headlight switch will, but will not damage the harness. Symptoms of it failing are non-working intermittent wipers, non-working hazard lights, wipers that don't park, and of course non operational wipers. Replacement is about the same as the headlight switch. If the car is not equipped with a rear wiper, there will be an extra switch that apparently does nothing. Tell your friends it engages secret engine modifications.
Cruise Control Switch
The cruise switch is trouble free.
CPU
The CPU is located behind the drivers kick panel, hidden by a wiring loom. It controls such things as the turn signals, horn, warning beep, etc. Over time, the poor Mazda solder joints will begin to become intermittent which will result in the malfunctioning of the aforementioned devices. The usual fix is to open up the CPU and resolder all the big joints. This is not an expensive or difficult task to do yourself, but a dealer will want to replace the whole CPU. I don't even want to know what that would cost
Emissions Control Unit (ECU)
The ECU is the real brains of the car, coordinating everything from spark timing to fuel delivery to idiot light functions. Unfortunately, this device is subject to two types of electrical malfunction. The first is bad solder joints. Go figure, eh? The second is bad grounding. As the car ages, the ground connections dirty up and corrode. This makes them intermittent and high resistance. The effect on the ECU from both these conditions is erratic operation, which can cause all manner of engine related problems. Perhaps one of the most common is the infamous 3800RPM hesitation. Coming up to 3800RPM, the engine may hesitate horribly. This is usually related to ECU problems. Cold solder joints can be repaired by resoldering the ECU and the grounding problem can be fixed by regrounding. A dealer may want to replace the whole unit though, and this would be at great cost.
Dead Horns
See "CPU"
Heater/AC/Fan Controls
The device that controls the heater, A/C and fan is referred to as the logicon. It is subject to the same soldering problem as most other parts in the car. Failures in the logicon show up in several ways. You may not be able to adjust the fan speed, adjust the air mix or change the air outlet locations. There are also several motors that control the flow of air. The one you want to be concerned with is the air mix motor. It controls the ratio of unheated/cooled air to heated/cooled air. If the logicon has fried, it may take the motor with it. If the motor has fried, it may take the logicon with in. You can repair the logicon yourself by resoldering the joints, but beware of price if you take it to a dealer. They will probably want close to $400 for a new one and it will be subject to the same types of failures as the old.
Stereo
For the most part, the stereo is trouble free. If it does fail, it will be due to bad soldering. The most common symptom is intermittent sound from one or more speakers, failed displays or inoperative controls. The radio can be repaired, but if it is removed you might as well install a good aftermarket unit. This will probably cost less then replacing it with another Mazda unit.
Power Antenna
As with most other power antennas, the unit on the RX-7 takes a lot of abuse and will wear out over time. If the motors runs (which you can hear in the rear drivers side) but the antenna doesn't move, the small plastic push strip has broken of come off the gears. It can usually be repaired with a minimum of fuss. Don't expect to find a good power antenna at the wreckers. If the motor does not run, first check the fuse. It may have been removed to keep the antenna from freezing up in the winter. If the radio is aftermarket and the antenna doesn't work, chances are that the relay required for the ground activated antenna (opposite of normal) was not installed. Oh, and regardless if the antenna is working or not, these cars get horrible radio reception.
Power Windows
Over time, the power window switches will tend to build up a carbon coating on the contacts. This usually leads to less than ideal window operation. The fix is to replace the switch, or use fine sandpaper to clean the contacts in the old ones. Personally, I would replace rather then repair as the sand paper will take the nickel coating off of the contacts.
Transmission/Drivetrain/Suspension/Brakes
With a few minor problems, these components of the car are reliable and trouble free. As long as the car has been cared for you shouldn't find any problems in this area.
Shifter
Don't be too surprised if the shifter is sloppy. The shifter bushings in these cars will fail over time and need to be replaced. The job is not complicated or expensive and is easily done in an hour. Don't worry to much about it.
Transmission
It goes without saying that the transmission should shift smoothly and easily. However, it will feel a little more notchie than other cars. Also, the 2nd gear syncro may be worn out, resulting in a grind when shifting quickly into second. The only way to fix this is to replace or rebuild the transmission. This is a common problem in the 2nd generation RX-7, so don't count on another car's transmission to be perfect either. Another common problem is noise. If the bearings are worn (mostly due to old or no transmission oil) they will provide a constant whine while the car or transmission is in motion. The only cure for this is a transmission rebuild or replacement, which is expensive. Note that the transmission may last for many more miles with this condition, or it could die next week. To check the level of transmission fluid, jack the car up so that it is raised and level. Now remove the fill plug from the drivers side front of the transmission (right near the starter). Stick in your pinky finger. You should be able to feel the fluid level. If you cannot feel it, the fluid is low and there is a leak somewhere.
Clutch
Make sure the clutch is not excessively worn (slipping) by shifting into a higher gear and then getting on the gas. The RPMs should rise as the car's speed increases. If the speed of the engine spikes but the car accelerates slowly then it is a good indication the clutch is slipping.
Driveshaft
As with any older car, the u-joints on the driveshaft are probably near or already past their useful life. This will show up as a very noticeable vibration when the car is moving. The problem here is that the stock Mazda driveshaft does not have replaceable joints, so you need a whole new driveshaft. However, do not buy the Mazda shaft if you can help it. Get an aftermarket shaft with replaceable joints to avoid this whole problem again.
Suspension
Listen for bumps, thumps and other things. No side of the car should sag, and it should not bounce up and down when you push on it. Excessive nose-dive while braking is bad, as is squatting when accelerating. You may notice some negative camber in the rear wheels. Toe in may also be present. Most RX-7s have a little negative camber so I wouldn't put too much worry into it. The toe in is due to the Dynamic Tracking Suspension System, and will straighten out when the car begins to move. The shocks should not leak oil, and the springs should not sag.
On cars so equipped, the AAS (Auto Adjusting Suspension) will probably not work. The system didn't do much anyway. If it doesn't work, odds are it has been disconnected, the struts have been replaced with standard struts (good) or the 10+ year old suspension is just worn out. The system was just a gimmick anyway, and a true sports car does not need such frivilties.
Steering
The car should track straight and no strange sounds should he hear when turning the wheel. If such sounds are heard, the ball joints and/or tie rod ends are probably worn out. They will need to be replaced and the car will have to be aligned.
Brakes
Needless to say, the brakes should work. They should feel fairly firm, and not drop straight to the floor. No pulsing should be felt. If it is, one of more rotors are warped. The brake lights should come on when the brakes are applied, and the parking brake should firmly hold the car on a hill. Applying the parking brake should also light the "BRAKE" idiot light. On application of the brakes the car should not pull to one side. If the car is equipped with ABS, find a deserted wet spot and slam on the brakes. The ABS should kick in. Also check the fluid. Black brake fluid signals neglect, or a history of cheap brake jobs. Be wary of such a car as there are probably hidden brake problems.
Tire Wear
The tires should not show any weird wear patterns. Most likely, the rears will be worn more than the fronts. This is normal for a RWD car as most people don't rotate their tires.
Bearings
Jack up each end of the car and try to rip the wheel off with your hands. You shouldn't feel any play or hear any clicking. If you do, the bearings or races are probably worn. One note about the front wheels: the bearing and hub are integral. That is, if one is bad you have to replace the whole assembly. This is expensive. Remember that bearings are a wear item on all cars and will need to be replaced/repacked at some point. Ask when this was last done.
There, I think that's just about it. Don't take this list to mean that the RX-7 is not a reliable car. For the most part, any used car will have a similar list of quirks. Hell, any new car will have the same thing. Remember the airbag computer failures on the 2001 Impala? Good luck in your search, and happy rotoring.
Turbo II
This document is the companion to How To Buy An '86-'91 Non-Turbo RX-7. The non-turbo document contains all the buying information common to both models of RX-7s. This document contains the turbo specific information. It is very important that you read both to get the full picture. It is best to read the non-turbo information first, then head back here to get the turbo specific stuff.
For the most part, the turbo RX-7 is very similar to the non-turbo, with some suspension, drivetrain, braking and of course engine changes. These differences are covered below.
The Engine
It is hard to make a judgement on the "average" life of a turbo rotary since it is very dependant on the care it has received. Nevertheless, the normal guess at average life is around 100,000 miles, but I have seen engines that were still nearly prefect with over 175K on them, as well as engines that were blown at 50K.
Compression
Checking the compression in a turbo rotary is very important. The engine is under much greater stresses when pressurized, which therefore relates to more wear and shorter engine life. Be especially careful if the car is modified, as boost increases will put even more strain on the engine. Look for an upgraded fuel system. Once the boost is increased past a few PSI, extra fuel will be required to prevent deadly detonation.
Oil Consumption
Oil consumption is very slightly higher on turbo cars, but it is hardly noticeable.
Smoking
Aside from smoking caused by worn seals that both the NA and turbo models can suffer from, smoking can also be caused by poor seals in the turbo. If the compressor seal is bad, oil will bypass into the intake tract and be burned by the engine. This is easy to spot since the car will smoke during long periods of deceleration as the engine vacuum will draws oil past the seal. Excessive amounts of oil will also be present in the intercooler and piping. If the turbine (exhaust side) seal is bad, there will be a constant flow of smoke from the exhaust, which will increase greatly when the car is driven under boost. If you can remove the precat/downpipe from the rear of the turbo, you will most likely find oil inside.
Any smoke coming from the turbo will be blue.
Overheating/Temperature
The turbo cars do run slightly hotter than the non turbo cars.
5th and 6th Ports
Turbo cars don't have them.
The Turbo (and related)
The turbo is of course the fun part of the Turbo II. There is nothing spectacular about the turbo system in the TII, save for the twin scroll system employed in the '86-'88 cars. Therefore, a few simple checks will help determine the condition of the turbocharger and related components. Note that the turbo is located at passenger side of the engine between the frame rail and the engine itself.
Turbocharger Heat Shields
Check to make sure the metal heat shields are in place over the turbine (exhaust) section of the turbo. These shields make a large difference in underhood temperature since the turbo is a massive source of heat.
Turbocharger Oil and Water Lines
Inspect the turbocharger externally and check for oil and water leaks. This may be difficult if the stock heat shields are still in place. Also check the lines where they meet the engine. Repairing any leak is normally straightforward, but it may not be so straightforward to actually get to the leaking part (normally a gasket) depending on which line is causing the leak.
Cracking
The turbos have a habit of cracking on the turbine side. Normally this happens internally and therefore the cracks are not visible on the outside. However, if you see cracking on the outside (specifically on the flange where it meets the manifold) then it is a sign of severe cracking, which will normally mean replacement of the turbine housing. This gets expensive. The same goes for the manifold. Large cracks in the exhaust manifold will mean replacement, which involves pulling the turbo. Lots of labour for someone who has not done it before.
Turbine Shaft Play
Remove the black plastic air duct that goes into the turbo (the turbo inlet duct, or "TID"). Now, with your fingers, give the compressor a spin. It should spin fairly freely and smoothly. There will be some dragging since the bearing will be stiff without it's oil jacket (only present with the car running), but it should be smooth throughout it's rotation. Now, alternately push and pull on the shaft. It should not move. If it does, you are looking at severe bearing and shaft wear, meaning replacement or a rebuild of the turbo. Very expensive. Apply pressure on the shaft, trying to push it left and right. Some play is normal, but it should not be excessive (compressor should not contact the housing). This play is caused by slack in the bearing, which is taken up when the oil film forms and the shaft "floats" on it's fluid bearing. While you're there, look for excessive oil in the compressor housing. Some is normal, but large amounts mean a turbo rebuild.
Twin Scroll
The '86-'88 TIIs employ a system called "twin scroll" to help combat turbo lag. Basically, at low RPMs, a flapper door inside the manifold closes and shuts off one of the two exhaust paths to the turbine. This causes the first path to direct exhaust gasses to hit the turbine wheel at a very sharp angle, thus quickly spooling the turbo. As the engine speed (and thus exhaust gas flow) increases, the flapper door is opened to allow the second exhaust passage to flow, thus allowing the turbo to flow to it's full potential.
This system relies on a solenoid, flapper door and actuator. Unfortunately, there is no easy way to test it. Jacking up the car and manually pressing on the actuator (front of the turbocharger, big silver can) will verify the assembly moves, but will not tell you if it works properly when the car is running. Fortunately, the twin scroll system is pretty reliable and failures are uncommon.
The twin scroll system was removed on '89+ cars due to better turbo design.
Intercooler and Piping
The intercooler (located on top of the engine) should be free of large dents. There should be no holes, and the fins should be straight and not filled with crud. A dirty intercooler is easy to clean, but one that has most of it's fins bent will be very ineffective and will need to be repaired or replaced.
The piping to and from the intercooler should be in good shape, with no holes or large dents. Carefully inspect the rubber hoses and check for cracks. It is common to find large cracks which will show up as a boost leak (low boost when driving, loud hissing noise). They are fairly inexpensive to replace.
Boost Pressure
If you have an aftermarket boost gauge available, check the boost pressure. The boost on a stock car should read 6.2 PSI. If the car modified, expect more boost. The pressure you see will depend on the modifications. Low boost can have many causes, from a clogged air filter to a dead turbo. Keep this in mind.
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