blkbird

iTrader: (28)

I started noticing that my oil pressure is going down little by little. At first I thought it was the OPSU, so I replaced it with an new AC delco. It was working good at first but now it has me wondering. OK, here is how it happens. When I start it up the o/p is about 42psi on a cold start and once warmed up is about 38-40psi. I drive it without getting on it and at about 40psi in 6th doing about 70mph. Now after i come to a stop it drops down to about 28-30psi at idle. Sometimes it show that and sometimes it show 38-40psi at idle (both reading while the car is fully warmed up). When I did my cam swap a year ago, i put in a brand new LS6 oil pump and my pressure was good (42psi idle and 45psi driving). When I turn on my A/C it drops to about 25psi at idle. Should I worry about this?? The motor isnt making any noises and the pressure does go up when I step on the gas. Any thoughts??

67Firebird455

iTrader: (27)

That's strange. Try a manual pressure gauge and see what kind of reading you get. I wouldn't worry too awful much just yet, that is quite a variation though, considering they're both tested warm, not sure...

blkbird

iTrader: (28)

I know, it baffles me also.....

3.4camaro

iTrader: (1)

that's plenty of oil pressure. My 3.4L had 5-10psi a idle. You should not be worried.

Asmodeus

I don't think it's the pressure itself that's causing him to worry. I think it's the change in pressure over time he's been noticing that has him thinking.

blkbird

iTrader: (28)

Yes, it has slowly been decreasing over a period of time.