hey guys wondering if u can help me out i got a b20 z10 sleves o-ringed fresh head has been machined and checked for leaks gsr . fresh head bolts after a few passes car will not overheat but coolant overflow will pass its max point and at times it will spill ive done a leak down on each individual cylinder for 10 min each ok no bubles on coolant leak test ok possible do to poor air flow ?or coolant lines on turbo ? the way there routed making high preesure wondering if anyone had this problem ? maybe theres a better way of rounting coolant lines ?i have mines from back of coolant pipe to the top radiator hose on the nipple gsr head by bleeder bolt thanks .

 

is your radiator cap good?

are you boosted when you see coolant in your overflow?

platinum

 

I'd start with a new radiator cap.

 

i had the same thing, check radiator cap, thermostat... if those two don't wory it could be a headgasket. which in the worse case scenario, that happen to me i changed it and the over fill stopped happening. it happen on my freshly built motor to man

 

I'm having the same problem as you and I just replaced my rad with a Fluidyne. I'm also losing coolant somewhere. I'm thinking head lift.

 

I was overflowing too one time, and I switched to aFluidyne radiator, switched thermostat, radiator cap, and slim fans only to find out it was the headgasket all along.

 

rad cap, headgasket