Driving today and suddenly smelt coolant. Looked down at my gauges and the stock temp gauge was way up near the top. Pulled over and turned the engine off straight away. Coolant was piling out of the overflow tank but there were no leaks or anything. Did a bit of checking around and managed to work out that it was the thermostat that was stuck closed and causing the overheating. I've replaced it with a working thermostat and driven home (drove for about 45-60minutes after I had replaced it).

Now I felt nothing different after putting the new thermostat in, but have read about the rotary being so susceptible to overheating. What are the potential hotspots (no pun intended) for overheating damage in the engine, and is there any way to test for any damage?

 

remove engine disassemble....other than that if ur power seems the same and its not overheating and coolant isn't pissing out of the overflow anymore then i think ur fine. u used a oem thermo right with the jiggle pin at the top. otherwise get a oem aftermarket ones are ****.

 

Yeah, power and everything else seems good so it seems like I might have dodged a bullet. The themostat replacement was a used one out of another FC just to get me home. Am gonna order an OEM one on Monday. Could get a generic JDM one from the parts store but after what people have said I think I'll go with a Mazda original.

 

You are allowed 1 overheat on your engine

 

Well I'd better hope the previous owners didn't have any then!

 

I bought my 1990 rx7 tstat from rx7store. It shipped in 6 days to so cal it was like 38 bones which is awesome cuz its oem mazda

 

I blew the radiator in my old first gen and ran for a while with the temp gauge up high... No lasting effects.

Sometimes you win, sometimes you lose.

I think a compression check and coolant pressure/leakdown test will be definitive tests if it's done anything.

 

The front iron can crack at the bottom exhaust side and allow exhaust into the cooling system. I'd recommend a champagne test and see how it is. If that goes good, consider yourself lucky and keep on driving.

 

If anything is cracked and leaking, the best test is a coolant pressure test. You can do this with the tool or by running the engine and letting it build up pressure. The cap is rated for 16psi. If you get the car hot and slowly remove the cap, being carefull of course, you should hear pressure escape when you twist it open. This at least will tell you if your system can build pressure. Other than that you will need the tool and some know how.

 

Yeah this! I overheated my car in real bad dead stop traffic because the e-fan wasn't operating properly. No shoulder to pull over... I let it cool off and started it again and ran it hott another mile or so down the road to a shoulder. I thought the engine was FOR SURE done it had overheated so bad there was maybe half the amount of coolant in it.

Luckily all was well... power still seemed fine. I've yet to do another compression check but I think it'll be the same as before.

Matter of luck I suppose...