LS1Aggie09

iTrader: (25)

I have noticed lately that my cars oil pressure has been dropping. It used to sit around 40 to 45 psi at idle and then get up to about 75 under load at high rpms. Now my pressure sits at about 25 to 30 at idle and when i accelerate in low rpms, the pressure actually DROPS about 5 psi until i let off the throttle at which point the pressure returns to about 30. SOMETIMES the pressure will sit at 35 to 40 like it should but then 5 minutes later it has dropped again.


What could be the issue? I am trying to do a little bit of research...but haven't found much yet. Could it be a lifter or worn components increasing clearances?

I have a 02 Z28 (which i thought had the LS6 pump from factory?) with near 130k miles on a stock longblock and T56. I have oil seapage at the rear main seal. Longest my car has been without oil change is 3200 miles and I always use Non-Synthetic Mobil Clean 5000 5w30.

Thanks! I hope it isn't much or I am paranoid but I know that I have high mileage too...

-Karl

1 FMF

iTrader: (1)

has it been getting warmer out?
higher oil temp = less viscosity = lower oil pressure at idle. When you first start the car the oil is cold (less than 100F) so it is thicker and you have higher more consistent oil pressure. now that's it's getting warmer out, the oil gets hotter faster and at idle you observe slightly less oil pressure, completely normal for a 5w30 oil. With over 100k miles and being in Tx i would use a 15w40, in fact i'm in CT with < 50k miles and I use 15w40.
As long as you're at or above 20psi at idle, running a 5w30, and the pressure immediately increases when rpms go up to 1500-2000 then there is no problem. Either use a higher viscosity oil, or figure out how to decrease your oil temp.

1sick'98WS6

iTrader: (19)

Does your car have a knock sound coming from it? If so it is a spun rod bearing, otherwise if it sounds fine and runs fine, I wouldnt worry

sscamaro1384

iTrader: (163)

its probably the rear main seal oil leak u have. i have the same problem