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Oil Pressure

Posted: September 12th, 2006, 4:16 am
by slimsmedley
i have an autometer oil pressure guage installed and was wondering if anyone could give me an explantaion of the vary oil pressures i have experienced. During startup of pressure is around 60psi (high obviously), then after idling for a while it drops to 20psi which seems fairly normal. When i have the car serviced with new oil it runs at 65-75psi on startup, then 25-30psi on idle after warming. It receives the correct amount of oil. After a few hundred kms it drops again. Why do i have this variance?? Am i buring oil slowly? it doesn't seem to smoke at all, and i have no oil leaks under the car...

Posted: September 12th, 2006, 10:55 am
by lakersfan1
Colder oil is thicker oil. Thicker oil gives higher pressure readings.

Older oil gets contaminated over time with gasoline and water. Those are thinner than oil, so hence lower readings.