Oil Pressure

Posted by Reyman R. Branting On 2008/2/27 13:40:07

Diagnosis from afar --

Yesterday the temperature was in the 20s in Pittsburgh. I started my 55 400 which has 15W 40 Shell oil in the crankcase. The oil pressure needle pegged on high. I drove the car about three miles, the engine warmed up a bit, and the pressure fell to about 1/4 of the gage at idle. During the summer, the warm engine oil pressure is in the middle of the gage.

It will be awhile before I can investigate. Any guesses on the huge change in pressure? The engine presumably had 30,000 +/- miles on it when I bought it. The oil pan was gunked up and the piston rings stuck. Compression was so low the engine would not start.

Cleaned the oil pan, checked the mains, had the head reworked (cleaned up and valves ground)flushed out the block, installed new rings and an Aller oil pump and put it back together. No valve clatter. The car has been driven less than 50 miles since reassembly. The valves were still quiet when I discovered the oil pressure was so low yesterday.

Any thoughts on what happened? I fear that some gunk plugged an oil line temporarily, just long enough to ruin the bearings, then flushed through.

Bernardi