Okay, why is oil pressure going UP at idle and DOWN at speed??

Posted by 1929PackardGuy On 2022/5/30 9:00:12

Took Sophie out this morning for a short drive as it's been too hot lately to drive her. Again 1929 Club Sedan 633, restored 22 years ago. I did get the springs issue resolved BTW.

Odd thing this morning, oil pressure was normal when she was cold, 40 psi pushing to about 45 at speed. On way home (10 mile trip total), she was running happy at 170 degrees, but I noted the oil gauge was actually going UP to 50 psi at idle, but revving the motor the psi went DOWN to 40 and at speed she was usually at 40 psi. The opposite of what I've usually seen to be the norm - once warmed up, the gauge reads higher at idle than at higher rpms.

I'm in Louisiana, it's darned hot down here, longtime user of Lucas 30 weight oil with the high zinc content. All my old cars have always seemed to love this stuff. Changed the oil and cleaned the screen and such last August, about 500 miles ago.

Any ideas? Thanks!