OK, the coolant can only go two places, that is an external leak, or internally, so if the pressure test has been done correctly and there is no external leaks, it must be an internal problem, you can have a head check done, this is a chemical test done in the cooling system, that detects exhaust gasses in the coolant, this is a sure sign of a combustion leak, get this done next.
Mark (mhpautos)
Tuesday, November 18th, 2008 AT 5:42 PM