Why does the water on a 2000 Chevy Venture pressureize when car is cold?

Answer 1

well to tell you the truth i think your head gaskets are leaking. if you still have that eco friendly purple stuff in it without a long over due change, chances are it ate away at your gaskets. I have a 2002 3.4 warner bros edition. and I pressure tested mine and she built up slowly to over 25 psi and faster if I rev the motor. After removel I found the gaskets were ate away in seven places. If it's not too late trade it in. don't try sealer on it it won't work if your building pressure in the system,only if its leaking on the outer jackets. if your lucky ! most of those sealers don't work at all. people thrive on makin a buck on your hopes every where you go. good luck!