cylinder head ?

[jtdb8]

ok this is something that has been bugging me for awhile. well i will say 3 years ago i burned a valve on my gsr head. ok i replaces the valve an had the machine shop pressure test the head an surface it. i installed itr pistons. i put it back togather an i noticed that the rad would still hold pressure after the car had sat for awhile. it could sit for 2 days an i take the cap off it release the pressure. drove it like that for awhile. ok pulled the head off some more work put head studs in an i still hadthe same thing going on. ok this last time i had screwed myself an blowed the headgasket. i had another head so i had it worked an what not, swaped them out "still head studs" an the prob is gone. i have been racking my brain on what could have gone wrong with that head to cause that to happen. i just want to see what any body else can come up with.

[jtdb8]

No ideas I see.

[green91]

A few options: Either the HG didnt seal or the head had a crack, you had an air pocket in the coolant you inadvertantly fixed when u replaced the head, other cooling system issue?

You should ALWAYS do a block test before yanking the head off for a HG concern, then you will actually know if you've got exhaust gas in your cooling system rather than just guessing.

[jtdb8]

I know when I have a head gasket blown. And I had that head off twice before I used the other head.

[green91]

HG isn't the only thing that will cause residual pressure in the cooling system after the vehicle sits.

[jtdb8]

HG isn't the only thing that will cause residual pressure in the cooling system after the vehicle sits.

I know.I should have specified. I didn't pull the head those times to fix that problem.

[BLK JDM]

The machine shop may not have decked the head correctly and it may have still been warped causing the headgasket not to seal all the way around. Or they decked the head too much.

[jtdb8]

The machine shop may not have decked the head correctly and it may have still been warped causing the headgasket not to seal all the way around. Or they decked the head too much.

that would cause it i guess. with a gsr head and itr pistons.

[xero_xero]

the problem with telling if it was the machine shop not properly gringin the head is that one you torque it down and run it through the first heat cycle, it undoes everything the machineshop did.