My second gen. has been giving me a lot of **** lately. the coolant has been building up in reservior. There is no leak in the coolant system and when I run my heater it seems to help a little. Any help please?

have you checked your thermostat? I really don't know, just trying to throw out a suggestion.

if it fills the overflow, you might want to check the caps, its also possible thats theres a leak



mike

how hot is it running? maybe your radiator is clogged

I think the first things you should check are the thermostat and the radiator cap. I had a problem similar to what you're describing and a system flush combined with a replacement of these components completely solved it.



If you're going to replace them, here are some tips:



- ONLY use the Mazda OEM thermostat. Pep Boys, Autozone, etc. versions just aren't as good and won't last. Mine only cost $15 at the dealer.



- Be very careful when tightening the thermostat housing bolts. The housing is plastic and the heat a rotary generates makes it fragile. Have some JB Weld nearby in case a fracture occurs.



- When draining the radiator, be careful with the radiator drain plug. It's made of nylon and susceptible to breaking. You can also actually drain the engine's water jacket too. There is a drain plug right inside the motor mount. It may sound strange, but it's true.



- Make sure your new radiator cap is rated at 13 lbs.



- Stay away from orange coolant. It's corrosive to a rotary engine's seals.



- Depending on your location, a 50/50 mix may not be necessary. I'm in high-heat Dallas and opted for a 70(H2O)/30(coolant) mix. The water is more responsible for the cooling, while the coolant is there more for its anti-corrosive properties to keep the system healthy.



- While you're at the cooling system, it's a good idea to replace the radiator hoses if they're old.



All of these suggestions are pretty much the standard "first step" in troubleshooting a cooling problem. It's not only because they're usually the first components to fail, but also because they're easily accessible and inexpensive relative to the other, more major, components of the system. If addressing these components doesn't fix your problem, you'll have to look at things like the fan clutch, the water pump and the radiator itself.

couple of things, if he has an S4 the thermostat housing is made of metal not plastic like the S5. Be sure to use plenty of PB blaster when you take them out and anti sieze when you put them back in. Also be prepared for one if not both of them the break.

Very informative post attomica.

Since I found this post about coolant mixing.. I have a question:



If I'm in Florida, where the temp stays above 60F most of the year, why not run 100% distilled water for coolant? I can see that as not practical during the winter because of freezing possibilty.. but all that freezing issue stuff aside.. any comments?

Antifreeze is also used to prevent corrosion. I think you might have crap growing in your cooling system if you did that. :-/

how bad is the orange coolant? I have it in mine.