A little background first...this a quick spec list, it was all carried out last year at the cost of £8k total!



Street Ported Engine 6k miles ago

Recond twins

Power FC

Feed Rad

New HKS Filters

New Larger Downpipe

KSP full exhaust system no cats no silencers

New Exedy twin clutch

New Plugs

New Leads

HKS FMIC

Running 316rwp on stock injectors @ 98% duty



Iv had an overheating problem for the last 4 months now. The car can get to 115'c! The filler neck to rad hose pressurises. It spews out coolant from the expansion grommet. The car has not been driven unless to test if it does overheat, which is only up and down the road 1/4 of a mile...the car idles fine with no champagne bubbles & doesnt chuck smoke out of the exhaust. It starts first time everytime whether hot or cold.All the belts are fine, in line, no slipping & connected correctly.



...This is what has been done to try and solve it...



1. All the coolant pipes in the engine bar the turbo hard pipes have been replaced.

2. All the AST pipes have been replaced

3. Some of the vacuum hoses have been replaced

4. Air pump has been removed

5. A/C pump has been removed

6. Fans have been replaced

7. Fan wiring has been replaced

8. Water pump has been replaced

9. Water pump housing has been replaced

10. Therostat has been replaced

11. Thermostat housing has been replaced

12. AST has been tested & replaced with stock & Pettit Racing

13. Compression check has been carried out, all ok

14. Combustion check has been carried out, all ok

15. Radiator has been flushed with caustic soda twice

16. Filler Cap has been replaced

17. All the clamps/jubilee clips have been replaced

18. Radiator has been replaced from Feed to stock

19. The Heater Matrix has been disconnected & bypassed



20. I Feel like Sh!t



& yet today it still overheated after being off the road for the last month having all that work done to it! Today was when the rad was changed, it overheated after 2 minutes compared to 40+mins with the Feed rad...?!?!



I spent all my time and energy trying to get it fixed but its still happening & nobody can understand why!!!!!!!!



PLEASE HELP!!!!! https://www.nopistons.com/forums/pub...1047683358.gif

My stab in the dark would be bad water seal.. But guessing that has been checked and ruled out.

Radiator getting good flow of air after intercooler? Power Fc stock settings one fan comes on in the mid 90s other one high 90s . This can be lowered to the low 80s with power excel or datalogit.

If the radiator is stood up right for fmic and not bled an airlock may be causing your problems , most after market radiators will have a bleed nut on the top. Last maybe the fans are wired up to run in the right direction ?

Fans are wired to be on from the ignition. So if the car is running they are constantly on. They are in the right direction. It overheats standing still now compared to before when it was fine whilst driving.



Iv been taught how to bleed the system by an engine builder and do it in the same way so shouldnt be any air in it whatsoever...also i use the hose in all of the coolant points i.e The throttle body spigot, the throttle body hose & the filler neck. This makes sure all the water is out of the system. Ontop of that i also burp it to make sure...

water seal, plugged radiator possibly i guess, dude when do your fans kick on and stuff that can do it, aldo you thought about maybe doin a radiator upgrade??

When you installed the new water pump how was the condition of the water pump housing ? If there is large amounts of pitting it can cause bad circulation. Having removed air pump do you still have the pump pulleyturning the right way?

What coolant/water ratio are you running?

And maybe I missed it, but did you do a pressure (leak-down) test on the cooling system?

If I have to make a bet.. Its your coolant seal.



Do a pressure test like Singal 2 suggested. If you loose pressure, you'll see where its coming from.. If you don't see it, its leaking into your combustion chambers. If that happens, you know what to do next. This is a very common problems in rotary engines. I've bought 8 or so engines so far and most of them are coolant seal failures.



Good luck!

I was kinda thinking that, since he indicated that the system was overpressurizing in just a quarter mile of driving, but wasn't sure. And he said it starts easily, which (I think) would be a little unusual. Most coolant seal failures foul out the plugs to some extent, making it miss a little on start up. But maybe that's mostly a function of WHERE the coolant leak is on the housing.

Everything covered by you guys has been carried out already...





The fans are wired so they are constantly from when the ignition is on & are new fans (tried 3 sets now)

A coolant pressure test has been done yesterday with no leaks

A radiator pressure test was done yesterday on the Feed one with no leaks or blockages, atm the stock rad is on the car

A coolant gasses combustion check was done again and was negative

The stock temp gauge doesnt move until 120'c+ which it used to get to before i got the PFC Commander that i now read off

The oil is ok and at normal levels

The thermostat has been changed to OEM once (The first one was OEM the 2nd was low temp)

The system is bleed properly because i was taught by an engine builder...i.e the throttle, filler neck & burped

The pressure caps have been changed



With regards to the water seals...it starts up fine all the time, no missing, no smoke, no champagne bubbles, no coolant gasses. Since i replaced all the hoses & pipes last week, put the stock rad on & put it all back together it overheats quicker than it did before. It starts pushing coolant out of the expansion from 80'c+ and the filler neck to rad pipe is pressurised from 50-60'c



There must be something im missing!

Rixio,



I know its hard for you to believe regarding your coolant seals, but its not that un common and by what you've listed, I say its your coolant.



First, bad coolant seals dont mean hard starting, smoke, or champagne bubbles. You'll usually see that when your coolant seals are completely gone and leaking like MOFO!



Also, I'm not sure how you did your pressure test but you need to do that over night. Not for couple of minutes. My guess is that when you crank the car and as the engine warms up, your exhaust gas (usually much much higher psi than your coolant) which passes thru your coolant seal and into your cooling system (hence over heating and over flow). But I could be completely wrong and I hope I am.



Good luck and let us know what happens... But do the cooling system test over night.. if you've already done that, I have no clue and only think you could do is take everything off and inspect all the cooling system parts.

I'm with herblenny....except for this^. If the test for hydrocarbons was negative, I just don't have any more guesses. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

But wouldnt there be some trace Hydrocarbons in the coolant & therefore show as positive?!?



How do you do a coolant pressure test over night? I just took it to a garage that specialise in performace cars and got them to do it, he said no leaks anywhere on the car and no drop in pressure...https://www.nopistons.com/forums/pub...IR#>/wacko.png



The entire coolant system is brand new! I bought it all and installed genuine Mazda parts! https://www.nopistons.com/forums/pub...R#>/unsure.png



https://www.nopistons.com/forums/pub...1047683561.gif

Maybe I misunderstood what he refers to "coolant gasses combustion check", I thought he was checking coolant thru his exhaust. Which might not show. Unless he meant he got the coolant annalysized and showed no HC in it. If thats the case, I have no clue.



Rixio, take a pic of your engine bay and post it. Maybe it could be simple as no belt around the waterpump pulley https://www.nopistons.com/forums/pub...IR#>/smile.png

Also i might add...when it does get to 90'c+ it tends to rev at 1600-1900rpm!!!!????!!!!



Will get pic in a sec https://www.nopistons.com/forums/pub...IR#>/smile.png

Iv done one better than a pic https://www.nopistons.com/forums/pub...IR#>/smile.png



Short video after an idle warm up...i left it for 5 mins then it started leaking out from the expansion tank grommet



http://www.youtube.com/watch?v=43bdGs4ePlI

I'm watching your video now and I still say its your coolant seal. I had the same symptoms as you. Coolant will over flow from reserve tank, and when the engine cools down you have to fill the neck again as your reserve is completely empty.



Another thing is that you have FMIC. I was told by someone who spoke to very respected rotary figure that when coolant temps are maintained below 90C the chance of blowing out coolant seals are low. The FMIC restricts air flow to the rad and tends to over heat the engine. I recommend making some sort of ducting for your radiator. I'm also working on this for my Blk FD.



Good luck!

I have 2 sets of spare fans so what i was going to do is join a set onto the front mount to get more air https://www.nopistons.com/forums/pub...DIR#>/wink.png



Looks like its going to have to wait though :(



So this means rebuild...again...after £8k/$14k!!

I think it's a coolant seal too, but I don't know about the FMIC being a direct or indirect cause. My guess, if it's only been 6k since a rebuild, would be a faulty seal to begin with, or it was installed improperly.

I understand that Teflon impregnated is the way to go over OEM.

My statement about FMIC only meant by its cause for higher coolant temp. Not direct casue of the coolant seal failure.



Sounds like your in UK? My guess is that they used an iron from an engine with already blown coolant seal. Probably the shop didn't spec the plates and housing carefully and just slapped it together. Thru my experiencing buying blown coolant seal engines (including mine) all were mazda reman. Every single one.



Well, my advice is get a shop with lapper to do the work for you. Also, make sure they know what lapper is and inspect their work before they assemble the engine. When the plates are lapped, it should be perfectly smooth without any swirl marks. Also tolerance should be near 0.



Regarding Teflon... I had conversation with someone about this and someone told me they are slightly longer than oem and might pinch during assembly.. I personally would stick to oem as oem seals are reinforced certain areas. But talk to your builder and see what he thinks. I'm just an enthusiast who's learning about this car... still..

F*ck F*ck F*ck



Yes im UK

The builder is a well known engine builder that has been doing this for 30+ years so knows his stuff & has a very good reputation...but...

Iv had sooo many problems though i doubt hes ever going to rebuild it for free...this started the week the warranty ran out as its been a full year since rebuilt. The last time i was there i had an overboosting problem which he attributed to a small wastegate..."It needs boring out" which to my understanding is not an issue unless running 400+hp...similair things have happened aswell with him so im abit reluctant to take it back..."Im kind of flexible about this sort of thing" he said when i asked if hed honor the warranty...



I dont know what im gona do atm, just really stressing about it!

I sounds to me like he knows his stuff. On that point of overboosting I agree with your builder. Your running a completely open exhaust and that WILL cause boost creep. It has nothing directly to do with a dyno sheet. And the only way to cure it is to add restriction back into the exahuast (ala: cat) or port the wastegate.

I was told by 7 different tuners that unless your running at least 100hp more than what you are you shouldnt have that problem...???



But then in that case shouldnt he have ported it in the first place because he knew the car was going to be running that much power...and nothing has been changed since he built & mapped it...

Probably. But it doesn't hurt to be an informed consumer either.

Rixio, I agree with Singal 2 about boost creep. It has nothing to do with HP... well, before I say that, most of the time more boost means more HP.. but regarding creep, its what he said, too free flowing exhaust system.



If your not shooting for 400HP I would put your cat back on. That will help from creep. Or get the waste gate ported (for stockers).



Regarding your builder.. well, For 2 years, I was shopping around for builders. Its not about how long they have been building but how well can they build. I've met some builder who was cocky and told me he's been building engines for 10 years and he doesn't have to spec parts because he could just feel it and know... Complete BS! And there are builders who just started and knows the ins and out and takes their time. That's the kind of builder you want. To take the rotary apart only takes an hour. To assemble it, maybe 2-3 hours... But cleaning and spec'ing all the little parts is where it takes time. My builder specs everything, assemble it, crank it on a table, break it in by going thru heat cycles, etc.. Costs little bit more but when i get it, I know its good!



Like I said earlier, make sure your builder has a lapper. Very few builders in US has one. And some say they send it off and its not lapped. I saw a pic of someone who send it off to some place to get it lapped and it was just put on a circular sander. Not the same.

Hmm...ok...abit confused now but nm...



Well thx for all the advice guys, i really do appreciate it...if he doesnt honor the warranty then im gona end up rebuild it myself because i just cant afford another £8k...i will send the parts off to another builder who i do trust but whos very expensive to rebuild & heavily port the block...if im taking the engine out i may aswell go single...To4Z i was thinking...or maybe GT3540R...



Thanks Again...will keep everybody informed https://www.nopistons.com/forums/pub...IR#>/smile.png