Arthur,
I really appreciate all the legwork you've done for me! The gauge w/ the old sender used to work intermittently-very intermittently. When it did work it seemed to indicate normal oil pressure- that is an 85 degree engine would register about 1.5 bar at idle and raise to full upon normal acceleration and then settle down to about 2.5 bar or so at 45-50 mph. I never observed the gauge fail, rather it seemed to either work or simply peg full on start up. As time and milage marched on, the gauge would work less and less often until now it hasn't worked for some time now. I just assumed it was an internal failure of the rheostat in the sender.

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Paul Hansen

1997 S500 (100,000mi)