I second the motion to completely disassemble and properly clean the engine and passages.
Even if it does not lock up next time you know the engine was put together somewhat dirty. If you don't clean the whole thing now you are asking for a short lived engine.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-