BOOSTLEAK

I've a '94 Rx7 the car has been running fine, but recently it has been spitting out coolant from the overflow tank after I shut it off and the buzzer would come on, the temp needle also goes up to about 10 o'clock when I try to start it, it seems like the coolant doesn't go back in to the engine and it has been forced out off the overflow tank, the car doesn't do this very often...the car is very easy to start, idle fine, and no white smoke whatsoever. Could this be a bad coolant seals or busted o-ring? I've an upgraded AST on the car so I doubt it's the radiator cap I also checked all the hoses and found no leaks. I was thinking maybe it's just a bad thermostat? Any ideas on what else would cause the coolant to come out off the overflow tank and not pressurizing it back into the engine rather than a bad o-ring or bad coolant seals?

Fumanchu

I am having the same problem. Can anybody help on this?

rynberg

The cap on the AST is bad or the wrong type. The proper cap has a mechanism to allow the coolant to return from the overflow tank back to the system. Replace the cap, they are cheap.

Fumanchu

Ok, so when I shut my car off, coolant leaks out of the bottom of the overflow neck where there is a seal. From searching the forums, it looks like I should replace both of my caps and see if that changes anything. Is that right???

adamrx7

Yep go w/ a 1.3 kpsi rad. cap. And I just replied to a thread above your about my coolent problem I had.

https://www.rx7club.com/forum/showth...hreadid=221758

Fumanchu

hmm...just started up my car with the caps off and only a few bubbles came up, so there is a coolant seal going bad, but slowly. It shouldn't be the problem b/c there isnt enough air to push coolant out of the overflow. Im going to go get some new caps right now to see if thats the problem.

ROTARYFDTT

iTrader: (4)

Well what type of bubbles were you seeing? They could have been air-bubbles. To my knowledge the type of "bubbles" caused by a coolant seal going are champagne bubbles.

depending on what type of bubbles your seeing I am going to go with rynberg's explanation. I believe this is the reason for your coolant issues.

Fumanchu

yea it wasn't tons of little bubbles. It was like 3 or 4 small bubbles. I am on my way to Kragen to see if they have a cap for me. I hope to god this is the problem.