have made the following observations lately on the vehicle in question.
These pressures and observations are made before and after an oil
change, and are the same:
cold idle pressure: approx 70PSI <gauge is the stock Chevy graduated
bar, so this is an estimate based on the markings on the gauge>
cold cruise pressure: approx same
warm idle pressure: 15-20PSI
warm cruise pressure: approx 40-50PSI. this is true if the throttle is
pressed at all off of idle <ie: if I'm sitting at a light and barely
tap the gas slowly, the pressure shoots straight to 40ishPSI>.
Idle pressures are with car in gear. If I put the car in park, while
warm, pressure raises probably 5-10PSI <I know I need a mechanical oil
pressure gauge for better troubleshooting, just don't have one>
Also-- if I nail the throttle while cruising, the oil pressure
fluctuates between about 35-60PSIm, rapidly, and then stabilizes.
Oil is Castrol Syntec 10W30. I live in Charleston SC <subtropical
climate>. Should I change to a different weight?
Given that pressure comes up when revs do, I don't think I have a
problem here-- but want to ask people who kow more than I do. For
comparison, my 1990 Jeep Cherokee with the 4.0 straight six with over
2000,000 miles on it, using same oil, has rock-solid 40+PSI indicated
at hot idle, and 60-70 at cold idle.
After this concern is addressed, I'm going to a bypass filter for my
transmmission and oil filtration. See it here:
http://www.bypassfilter.com/ . I am not affiliated with the product or
sales, just VERY impressed with what I've seen from several friends
who're running these. It's a GREAT way to save money, save wear, save
the environment <not that I'm a treehugger>, and reduce our dependance
on foreign oil.