My 94 rx7 is over heating and making boiling sounds from the top left of the engine. runs for 15-20 minutes n then overheats. when its cool, i try to put pressure in the top radiator by blowing in it and i can hear bubbles bubbling like you would if you blew in a straw in a glass of water. anyone know what this is from? does it sound like anything is disconnected or anything?

 

is it actually overheating, or just blowing it into the overflow tank/reservoir?

 

when its cold i blow into the top radiator and i can hear the bubbles in the resivor. but it will overheat after 10-15 minutes of driving.

 

If it's overheated more than once, just take it to a good rotary shop and have them check out the engine. They'll do a pressure test. You might get lucky and not need a rebuild.

Dave

 

I'd suggest this place in IN
http://www.banzai-racing.com/

 

I have always gone to A-Spec tuning and the engine was rebuilt about 7000 miles ago with 3mm seals and race ported. God i hope thats not the case. Pressure from what the rotors chambers? or coolant pressure? it its that, i blow it and it goes right to the reservior

 

Do you have the AST in place? If so, then I'm thinking you have a bad radiator cap on the AST which isn't maintaining the proper pressure in the system, and just venting all pressure to the overflow tank.

 

no i have the crappy stock one. i have noticed that if i fill the top radiator and close the cap. drive it around the block, sometimes the fluid i filled goes away but then sometimes its still there. do you think that the thermostat is not functioning properly??

 

i know exactly what ur problem is. u have a nasty air bubble in ur coolding system and the reason why ur getting the bubbling sound is cuz theres not enough water/coolant in ur system which causes the heat to rise.....ALOT! do u have a PWFC and commander, cuz if its boiling the temps are getting close to 125 degress, which is EXTREMELY BAD! dont let it get up to that while the engine is running or u can just say bye bye to ur engine. best way to get rid of that bubble is flush the cooling system ( the right way ) and add the coolant the right way. i'll post a link on how to do it in alittle bit. also i would upgrade ur AST.. i took mine off and if u want i'll sell u mine if ur interested. it bullshit and all that bs. PM if ur interested and i'll post the link for u.


-Tony

 

i ment to say " its polished and all that bs" sorry

 

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what psi caps are you running, the one on the waterpump housing is supposed to be a cap with no spring on the bottom, and the one on the AST should have a spring on the bottom, and stock is 13psi (0.9bar) and i upgraded mine to 16 psi for added insurance. Older caps lose their tension and can prematurely allow the water into the overflow.

I agree with the air bubbles in the system, its a PIA to get rid of all the air bubbles. You have to burp the cooling system and get rid of all the air.

 

Ahhh if you can tell me how to flush out the bubble, that would be awesome. if you can explain it idiot that would be good too...So you guys dont think it could be the thermostat?

 

I do not have a pwfc or commander i have an apexi ecu yes but not that attachment. it was professionally tuned by a-spec in illinois....

 

the cap are stock, so yes there is a spring on the one on the pump housing and the reservoir is the stock plastic one.....

 

i burp mine by filling it up then a combination of lightly pinching the radiator hose to push the bubbles out. as it goes down i keep filling it. Another way is by taking your palm and hitting the top of the filler area to cause pressure and a slight suction, and refilling as it goes down. I also monitor the water level for several days after and continue burping it. There is a special funnel thats supposed to make burping the system easy. There is some more info in the FAQ regarding it.

I would also replace the cap on the AST with a new 16lb cap (1.1 bar i think) If the one on the water pump housing has a spring then thats not the correct cap. its supposed to just be a solid sealing on with no relief. You have 2 options for this if its not the correct one. Buy the correct one, or by a higher pressure cap then the other side, such as a 19 psi with 16 psi on the AST, that will make sure if it boils over it goes into the overflow.

 

Delete the AST! Not helpful advice for the situation, but I tell everyone that has it to remove it.