My car is doing this after shut off. I get this little river of green once in a while. There is no sign of leakage at the Pettit AST cap or the OEM water filler cap.

Someone please explain this to me ...

 

be sure not to fill it when its cold, only when its warmed up, ...it needs room to expand as it warms up.....if you fill it when its cold, it will spew out....

 

Oh, OK. Then I'm allright, right?

 

I would replace the AST cap unless it's pretty new. It has a mechanism to allow the coolant to flow back from the overflow tank and this may be not working on yours.

 

Someone give him the bad news...

 

bad news is that your coolant seals might be going. your symptom is typical of a bad o-ring seal necessitating a motor rebuild...

 

What? You try and pull the cap off that thing when it's warmed up and you will get a nice surprize...Like coolant all over you and all over your engie bay type of surprize...

I bet the current status of you engine is stock, right? Well, there are these things called coolant seals and when they get old or have overheated they become damaged and cause coolant to leak into the engine...this in turns causes the pressurized coolant system to suck more air into the system through the leak...Well, with more pressure so the coolant has to go somewhere...it heads straight to the filterneck, then to the ast, then through the pressurized cap, then to the overflow tank, then all over your barke duct, then all over your driveway....Some things you will notice or can check for is, difficulty starting (kinda starts like foul plugs or something)...gurgling in the coolant system, wicked white smoke (more than usual) out the exhaust at startup, Champeign bubbles from the filter neck, and I can't think of anything else.

Sometimes people are lucky and it's just the cap to your AST that needs replaced, or just need to burp your coolant system...I wasn't that lucky...However, if your seals are in fack going, all hope is not lost (not yet anyway ) There's a product called CRC blockweld that can patch you up for a while...Some have had up to two year success before the inevitable rebuild...But others who start running high boost on blockweld tend to blow out the patch job...then you could repeat the treatment again and again until your just can't patch it up anymore...then that's when you go get your big phat ported rebuild (that would be the bright side of this equation)

Anyway, cheer up and go diagnose your problem and report back to us...

Good luck, my prayers are with you!

 

In addition to the items in the above post, check the hose from the AST to the overflow tank (condition and connections).

I would never put CRC in my car.

This is why not...

https://www.rx7club.com/forum/showth...hreadid=174747

 

I could have sworn I posted this exact response on that thread ...honestly though, think about it...you aren't going to stick CRC in a new motor with no probs...I called the guys at RX7.com and asked "if I put this stuff in is it going to affect the rebuild?" (since they are doing my rebuild) RP "No" If it does infact clog the radiator then put a $50 used stock radiator in there (if you are running an aftermarket rad) and clog the **** out of that thing...Big freaking deal, I clogged my stock crappy radiator and overheated my engine that's needs a rebuild anyway. I have a brand new Koyo sitting behind my futon now just for that reason, and it will go in along with the rebuild....and here I am running a FMIC with stock rad and CRC...If I didn't do the CRC I would have shelled out 5.5k about 3 months ago...But here I am, bad seals and CRC still kicking ***.

So this is what it comes down to...if you are going to need a rebuild anyway, (not saying that the thread starter is going to need one) why the hell not stick that stuff in there and get the most out of that old bitch?

 

check for a bad seal around the radiater and the plastic top and lower tank. If these seals are bad it will cause coolent to be dumped into the overflow tank, causing the overflow to dump excess coolent to the ground. I do not know if this was the problem that you were having, but this happeed to my 93 stock radiater and is known for happing to others.

good luck

joe

 

Really. Lots of hot things happening on that futon?

Dave

 

You got it buddy

 

Hmm. So are you saying the AST cap could be the issue(hopefully)? I did put a new one on there recently because the old one was leaking pretty bad. The thing is is that the only cap I could get had a higher pressure rating. Does this matter?

If it is the AST cap gone bad, will it show signs of leakage? Oh yeah, and there is no white smoke on start up. I had my first rebuild due to this two years ago, under extended warranty.

The othe rissue with my car is that I have a wicked Front Cover oil leak. Could this contribute to the coolant issue? I was told that this will cost me 1000+ to have fixed since the Front Cover is so inaccessible. This has me already thinking about getting a new motor.

I hope this isn't the case. But if it is, I'm just gonna have to bite the bullet and go put a new Motor on the credit card...

Thanks for the rsponses guys.

 

The AST has what amounts to 2 valves built into the cap. They allow coolant to flow out when the pressure exceeds the rating on the cap (the outer large valve), and back in after the car cools down (the inner small valve). If this inner valve gets stuck, coolant can flow out but never gets sucked back in.

It will not always leak when it fails, as when the smaller valve gets stuck.

 

Just wondering what causes the majority of o-ring failers?Overheating or just high milage.

 

combination of the 2