Damn car scared me today. Before I started her up, I changed out my O2 sensor for the new one(fixed one prob). After that I filled up the coolant from the filler neck side, and it took quite a bit. Then I took it out of the garage and let it warmup. I went to a friends house and parked it. When I came back out 10 mins later there was coolant on the ground. Felt it; was cold/cool. Checked overflow tank; completely full. Car doesn't smoke at all(20k on engine) and the ast pressure top was closed. So my only guess is that when I filled it up it went into the overflow tank, by means of the ast pressure cap getting stuck open. Cause it was still taking fluid(when I was filling it up) until I closed the filler neck and opened the ast. I have my Alum ast sitting in the garage, just need some teflon tape to install it. Better time then ever. I searched the forum before posting this, and so I did to add to anyone else's digianostics.

 

did u check ur hose from the filler neck to the overflow? the car uses vacumm to pull coolant/water from the overflow tank wen u turn of the car, if u have a cut, jus a tiny bit, it can be pulling air back in instead of cooant, but is ur coolant light on?

 

No light, but I just suspect the pressure cap was stuck open. So it gives me an excuse to get the teflon tape I need to install the Aluminum one. It has done this only this one time, and I know thats a fact cause I keep a very close eye on the car. That and I don't drive it but every other week or more.

 

Okay, I have had a similar problem. Can you explain this to me in more detail? Not too knowledgeable on the coolant system and pressure caps and whatnot.

Thanks

 

When looking at the engine bay the fillerneck cap is just to the right of the airpump. The AST is attached to the intercooler. IF your car is still stock. I need to take pics when I can...

What happened was I had taken off the fillerneck cap and the coolant level started to drop inside, so I added more and more. I knew something was wrong when it wouldn't stop so I topped it off and quickly put the cap back on. Then I took off the AST cap(the one with a spring assembly built in) and heard it "pop". So my AST cap had gotten stuck in the open/up position. By it doing this, when I added to the fillerneck the coolant would go down into the AST and strait on into the Overflow tank(behind the passenger side headlight). It had filled it up, and without thinking about it I started the car and let it warm up. After driveing for about 5 miles and parking it, I found(shortly later) a small(3FT diameter) puddle of cold/cool coolant next to my right front tire. A short inspection with a flashlight revealed the overflow tank full and had pushed the excess that it couldn't hold out. Nothing was wrong with my system other than the AST cap getting stuck open, which is bad, but didn't duplicate itself any more that day. An aftermarket alluminum one with a higher psi cap would work better and less likely to get stuck. Just need to install mine now.

Hope this was more detailed.