my truck blows coolant out the overflow when i run my chip and go over35 psi of boost but no coolant in the oil and the coolant is clean. when i run the truck wit the comp box off at 30psi its fine anyone have any ideals ,most likely headgasket and or strechd head bolts

 

Sounds like a combination of both. High cylinder pressures combined with higher levels of boost pressure may be pushing the head upwards just enough to leak pressure into the crankcase and thus blowing coolant out.

Remember that the cooling system is designed to run at a specific pressure when warm (regulated by the radiator cap spring), and anything beyond that will push the spring and be released to the overflow bottle.

Your edge comp box is probably altering both fuel and timing which can significantly increase cylinder pressures. This can push up the head just enough to leak pressure into the system. I would bet excess pressure is getting into the crankcase too and getting released through the vent tube. You should check that area out too and see if there is any seepage or fresh oil marks. This won't leak as bad as the coolant, simply because the crankcase is never completely filled with oil and the vent is well above the oil pan/sump.

You probably need to replace the head gasket and re-torque the head down to specs. You may also need to consider head studs and/or O-rings.

Hope this helps.

 

I could be wrong and don't mean to question ya, since I've never pulled heads off a Cummins...but won't that ruin the head gasket? The gassers I've rebuilt I've always been told that once you disrupt the head gasket, it can't be trusted not to leak and has to be replaced.

 

you are correct!

 

I stand corrected too.

 

thanks ya all