did you get the head milled?



if its filling up the overflow tank, than its definatly a blown headgasket.

that or your cap is screwed up.

 

about a couple weeks ago i put a new headgasket on and took the head to the machine shop and the said it was fine. i got a new radiator cap. and the car is not build presser in the radiator until a start to boost.

 

What kind of hg did you use? Composite, mls....

A while back, I chased my tale on a buddies car using composite hg's. Not relizing they are not structurally capable of holding the cylinder pressures we reach on our boosted setups. We pushed two composites then switched to mls.

If you used an mls gasket and had the head checked, my next thought would be the block may be warped or there may be an issue with the head bolts. However, I'm questioning the reality of head bolts stretching and heads lifting under boost. I have yet to discover how elastic the steel bolts are. I would think the aluminum threads would fail before the steel bolts, but that's just my rambling....

 

Flush your radiator out
Check for dirt build up in your radiator pipes if you squeeze them and hear a cracking sound they are stuffed.

 

Water pump, rad. cap, proper coolant mixture or bubbles in the system.