Do I have a cracked head?

[johnplogii]

After two or three passes my radiator builds up a lot of pressure & pukes some coolant in the overflow tank. I bought a 24 lb cap & that didn't help. It has been doing this for about 4 months now. I also tested the air in the coolant system for co2 but was negative. This tells me it is a pre-combustion leak. Anyone else have this problem? Any ideas?

 

[QUIP'6']

air in system probably from the water pump you have some waterpumps tend to airrate the water to much causing air in system

 

[johnplogii]

I forgot to mention there is a lot of foam in the radiator & overflow when it does this. If its just the water pump that would be great!

 

[BadAssGN]

I saw a ported head hogged out to far and it struck water... i think it was an exhaust port though...

 

[bison]

I think you are blowing compression over the head gasket at high boost. Im sure you didnt check for CO2 at WOT. If you did you would get CO2.

 

[johnplogii]

Is this common? What is the fix, new gaskets?

 

[johnplogii]

Also, once the co2 gets in there, wouldn't it stay in there untill the pressure is relieved?

 

[bison]

If you are using a metal head gasket you could try backing off the fasteners and doing a retorque. Do one at a time. If its a composite type gasket you better pull the heads. The CO2 may be trapped for a while but will be pushed out of the radiator first because its a gas and will go to the top of the radiator and out the relief valve.

 

[johnplogii]

They are fel-pro wire-loc's. Re-torqued them properly back when they were new. Thanks for the help.

 

[bison]

They are fel-pro wire-loc's. Re-torqued them properly back when they were new. Thanks for the help.

Ive seen a lot of problems in the past with those if the receiver grooves are not cut just right.