Over the weekend I tried unsuccessfully to flush with muriatic acid. The engine overheated rapidly and boiled over like Old Faithful.

I'm now pretty certain that there is a blockage in the water jacket preventing adequate coolant flow..

A couple times when I opened the petcock on the block, water dribbled out until I jabbed an ice pick in the hole and then it flowed out steadily. The weird thing is that there is no glop or sediment in the water.

I'm probably going to have to pull the manifolds in order to reach the casting plugs and remove them.

I will probably get a block test kit prior to tearing everything down just to confirm that the problem is not exhaust gas in the coolant. No bubbles are observed, however until the water starts boiling.

The other problem that's developed is that a crack that a previous owner repaired is now weeping. That will have to be addressed as well, once the blockage problem is solved.

I suspect whatever was used to patch the crack lost its bond due to the excessive heat. It's right down there by the petcock where these engines all seem to have cracks.

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)