bet

I have not owned my 993 during hot weather, until now so all of this may be normal. I also want to point out that I did an oil and filter change in March and put in (10.5 quarts) Mobil 1 0w40. I am trying to determine what is the “normal” oil pressure for this oil. I know as the oil temperature increases the oil pressure drops and theoretically the 0w40 should have a slightly lower pressure at any give temperature than a more viscous oil such as 10w50. As the ambient temperature has increased to the 80's and 90's and after the car is fully warmed up I have noticed my oil pressure at idle hovers around 2 on the gauge (bar?) whereas it use to be around 3 . Under acceleration and driving the gauge does not “peg” itself anymore but does register between the 4 and 5 (which seems normal). Since oil is the life blood I want to make sure I don’t have problem. Is this normal behavior during hot weather?

One last question. Does anyone ever experience at idle an occasional “jump” in oil pressure, where the gauge may jump for second from 2 to 3 and then back down to 2? Normal? or is this an indication of a problem? Thanks for the help.

911-TOUR

bet,

The oil pressure surge is normal, as long as it lasts only a momment. I only observe this at idle, not sure what causes it.

sean

J-McDonald

Since the oil pump is gear-driven, oil pressure will rise and fall with rpm's. Minor fluctuations in idle speed (say from ~850rpm to ~950rpm and back) will cause the indicated oil pressure to rise and fall.