I have a 50 Olds coupe with a 400 cubic in.67 Olds engine. When it is cold and first stars up, oil pressure is 65. Has Stewart Warner mechanical gauge. By the time it warms up to about 200 degrees, it will drop to as low as about 5 lbs. The engine has been completely rebuilt, all new stuff in the bottom end, roller lifter cam. Using stock radiator and aftermarket trans cooler. Has a turbo 400. Have driven it about 40 miles. I put in 15-40 weight oil after this first happened and it didn't help. Can anyone help me with this problem?
Have you checked the oil-pressure relief valve? Got similar trouble, and it was the valve..oil bleeding past it all time.
It is a goner, best sell it to me and rid yourself of the problem. In reality I am just jealous as I miss my 49 Olds coupe I sold years ago. Hope you get the problem solved. ~sololobo~
The first thing I would do is hook up a direct reading gauge to verify your indication system. Could be as simple as a bad oil pressure transmitter or gauge.
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