Packard Forum Index » Post-War (1946-54)

Just to be sure, you're using a new head gasket, correct? They cannot be reused one torqued down. I always coat both sides of the gasket with aerosol Coppercoat too.

I can only guess from here, but my guess is that you had a head gasket issue, perhaps related to a problem with a bolt too long, the gasket itself, or some flaw in the head or block that failed to seal.
Proper, 3-stage correct torquing in the proper sequence followed by proper re-torquing is essential.

If your engine has head studs, it is essential that all rust or gasket debris be removed from around them, right up to the stud itself. In the case of bolts, they need to be in good condition and the bolt holes must be clean clear to the bottom of blind holes and sealer needs to be used on any bolts or stud threads that go into holes that reach the water jacket. Usually, at least some of them do.