To All: After changing rear main seal twice…still leaked excessively…have retraced leak more thouroughly and found that lhe leak may be from what appears to be an incorrect ‘threaded plug’. Unfortunately this required dropping tranny, removing oil pan, pump, flywheel cover, housing etc. to expose rear of engine and the end of crankshaft and metal panel bolted on the rear of engine block
The excessive oil was around the plug and looked like it was leaking from there… the plug was removed and one can see that it did not match the threaded block hole. With engine on an upright position, the plug is located on the right sie of the block (picute below shows block upside down). When plate bolts and plate is removed, there is a soft freeze plug on the left and a ‘threaded plug’ on the right. The bolt size is 7/8" and the thread number is 14, with what appears to be straight type threads rather than sloted. Don’t know at this time whether the plug has a weep hole from top to bottom or just at the bottom or none at all. Again, since the one we removed appears to be the wrong plug, both in length and in type of thread, which may be why it’s leaking through the threads.
Anyone familiar with such a ‘threaded plug’ in mid year cars or later year cars…what is its function and where does that hole channel go to…? W30post, You mentioned a ‘blind plug’ that has a weep hole on it…is it located in the same area…? I couldn’t find any other threaded plug that has a weeping hole on it…? Anyone that has or knows where I can locate such a ‘threaded plug’, or anyone with an old '54 Olds engine that is willing to part out…let me know? Anxious to get this Olds on the road and cruise…!