perryinva

Same long 2hour each way trip, all interstate as the speedo post, but something else. Since I've had the car ( 4 months), my trips have been limited to 45 min tops. This was the first long one since I've been familair with the car. Everyone knows that oil pressure varies directly with RPM and oil temp. But once up to temp, the pressure stays solid for a given RPM. After about 1.5 hours on the interstate, I noticed that the pressure, at a given rpm would oscillate occasionally, maybe 0.25 to 0.5 bar, easily visible on the dash pressure gauge. It APPEARED to be related to road irregularities, almost like anything that would make the oil slosh around in the sump would cause a small pressure upset. I may have just never noticed it before, and it may be perfectly normal and why most auto makers damp their pressure readings. Autoenginuity verified that the pressure was changing while rpm was steady. Anyone else notice this phenom? Normal? NO loss of oil or smoke or performance issues at all, in fact got a steady 26mpg averaging 76 (real) mph. Checked the level today..not a bit lower after over 3k miles on the same oil change. Just curious.

clifforza

I know the sending units on these cars can be a P.I.T.A. Recently had mine replaced ('02 C4S) after a couple of cases of "heart in mouth". (Pressure suddenly drops to 0 while driving). You might check that out. Good luck. Cliff