Quote:
Originally Posted by NewArt
If it were the latter, wouldn't i see some evidence in the oil? It's a 3.2
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Not necessarily, that would depend upon how the head is cracked. As these heads often develop cracks adjacent to the valve spring and seat area, you can get a small crack that opens the water jacket to a combustion chamber. The car will run fine, but if you pull vacuum on the cooling system, air is drawn in from the combustion chamber and the vacuum bleeds off, usually slowly. While this is not an everyday occurrence, it has happened.
When we ran into it, we confirmed an issue existed by running a leak down test and found one cylinder with high leak rates; when we pulled the head and dyed it with a crack finding compound, two small cracks appeared near the spring seat.
As your system is already refilled, I would suggest doing a cooling system pressure test, if necessary with some Uview cooling system dye in it (that won't bother the cooling system at all, but will highlight any where coolant is trying to leak out under pressure).
These cooling system are typically tight under vacuum (we hold them at 25-26 inches for at least 15 min. before refilling the system). You need to track down where yours is losing vacuum as that should not happen.