after 20 minuets of running my 94 RX over heats and when you lift the hood up you hear like water is boiling near the front left of the engine. i hear it could be 2 things the water pump or the thermostat not working. now, i bought a thermostat but where does it go on the car? Can someone put a pic for me to see where it goes so i have an idea? i'm not that mechanically inclined but i can try. My engine was rebuilt by A_Spec Tuning 5,000 miles ago and want to rule out that it could in the engine but i cant. any one have a clue?its been sitting in the garage for over a year because of this....HELP.......

 

I'd suggest downloading the 94 factory service manual. You can find a link in one of the stickies at the top of this section. It will tell you how to replace the thermostat. BTW, I've not replace one before, but I have read how it is done in the Factory Service Manual.

 

you also want to double check your radiator cap. that'll also cause overheating problems as you have described.

 

luknoi

Hey man Im in illinois too..send me a pm and we'll see if we can meet up and fix your problem

 

air in the system?

 

do your fans come on? the boiling sound is the overflow tank being filled with hot coolant. your caps might not be holding enough pressure too.

 

Does the car have a aftermarket temp gauge? How hot is it actually gettingg? Is it getting hot and staying at the same temperature or is it shooting straight up to infinity...?

Knowing the above may help figure out the problem.

 

No aftermarket temp gauge yet. can you paste a link oof where i can get the service manual cause i cant find it. The transformers sticker looks good, im looking for a metal one to place teh Mazda logo on the hood but no luck. New radiator cap. My PM? What is a PM? yeah the fans come on. You say my caps, radiator caps or what caps??Temp on crappy OEM gauge just goes up till it cant anymore. What can cause the tank to be filling with hot coolant??

 

yeah your radiator caps. the one on the water pump housing is not supposed to have a spring on it it just holds the coolant in. the radiator cap on the AST should have a spring, and if its older it can lose tention. Mazda switched all the caps over to 10 psi (0.9 bar) caps, this causes the coolant to boil over at a lower temperature. personally i run a 16 psi cap, i would rather have higher pressure in the system and not lose my coolant and just keep an eye on the temperature.

You could also have air in your system, make sure you burp the coolant system completely. If you run one of the caps with the red levers on the top it allows you to bleed the air out after it reaches operating temperature. Burping the system should still be done though. Other then those simple fixes it could be your thermostat stuck in the closed position or not opening all the way.

 

ok,before you get i-yelled at,the thermostat is under the radiator cap thats on TOP front of engine.Three screws holds it together,with at least one of the screws being under the air pump belt(at least its that was on mine).As far as the thermostat itself,heres a suggestion:dont go to autozone!!Do everything possible to get an OEM(original equiment manufacturer)to ease things up.Call Ray at Malloy Mazda(look that up here on Search)and get it from him.While youre at it get the radiator caps from him as well,you wont go wrong.Thatll take care of the thermostat and caps(radiator)IF thats the problem.Also do a search on the burping tool,to help you out with air in the system.If you cant do any of those,seriously,have someone who knows about cooling(mazda)to do it for you.Good Luck

 

i made a mistake in my previous post, mazda switched over to 13 psi caps. (0.9 bar)

 

replace the ast cap make sure the cap on the water pump housing has no spring and bleed the **** out of your system till you have no more air in the system. if this doest work then start looking at your radiator and water pump. you can also pressure test the system to check for leaks.

 

I believe you can rent a pressure tester at AutoZone, that will probably reveal the source of your problem.

 

all right ill go rent one tomorrow, how much pressure do you pump and what? look for coolant leaks? Thats a new tool for me..

 

And where can i get a service manual for a 94 rx anyways?? Anyone have an idea? Chiltons and Hayes dont have one..

 

you can find service manuals through PDF internet files. There are several links posted throughout this forum for FSM downloads. I think the FAQ has links listed. The pressure test should be pumped up to whatever your cap holds, at this point the cap will start bleeding off the excess pressure. If it bleeds off sooner you will need a new cap. They aren't very expensive like 6 dollars or so at orielly a little more at autozone but they match prices too. You might want a higher pressure cap anyways, i prefer the added margin it allows.

 

i have not been able to get the pressure tester because there are non available at any car part/shop. not sure if i mentioned this but when i run it the only smoke that comes is from the coolant cap on top of the engine. the coolant level in the reserve does not go down at all. does that mean anything???