Maverick_997

pressure is getttin in my cooling system and i have a few guesses why.
just bought car about 3 weeks ago (1997 z28) dont have much history on car..
1. had to change the head gasket since it was already blown when i bought it. now im guessing a small compression leak somewhere in their.
2.could it be a bad cat?? ive heard people having built up back pressure in their causing lots of pressure to build up in the cooling system.
3.no real ideas for a number 3 but something new the car started doing since i adjusted the valves was that the car wants to run on for about a second after the key is turned off. bad valuve adjustment?? to tight?? to loose?? or caused by my presssure in the system??

all help will be greatly appreciated

Guest47904

Why do you say you have a pressure build up? In other words, what is your symptom?

Maverick_997

the car will shoot cold water out of the over flow after about 5 mins of idle and after i turn the car of let it cool down for about 20 min, the bleeders will have nothing but air coming out of them for about 6-8 mins.

Guest47904

One problem is probably the wrong pressure radiator cap. Try getting the proper one from a dealer, not aftermarket.

Then before you cap it off, keep filling the radiator with 50/50 as you run the engine until it won't take anymore and you see it circulating. Then cap it off and let it sit overnight to cool. Next morning fill it and cap it. Then run it.

G. McDonald

Given that you say you just did the head gaskets, you might want to double check that you have properly connected the two tubes that are attached to the radiator immediately above and below the cap. I believe if you cross up the tube to the coolant overflow tank and the pressurized line from the coolant crossover pipe (situated between the two heads on the back of the engine) then you can experience the type of thing you are seeing.

I believe that pressurized line fromt he back of the engine must be attached to the radiator below the pressurized cap and the line from the overflow tank must be attached above that. Perhaps your problem does not stem from this issue, but it might be worth a check.

Best of luck, let us know how it all turns out.