T-Bone98

When I start my Corvette my idle oil pressure is sitting anywhere between 39-43 PSI which I have heard is in the acceptable range for an idle. However, once the gets warmed up to an oil tempature of 160+ degress the idle temperature will fall down into the mid to high 20's PSI (24-29), I just recently changed the oil from Mobil 1 5-30W to Mobil 1 10-30W. Is this oil temparature difference between hot and cold idle normal for C5's? When the idle temp is in the mid 20's PSI and the engine is warmed up and I accelerate. I do get some slight lifter noise (tapping) although it is not heavy noise, but it is there and it stops immediately when I come off the accelerator. This noise does not happen when the car is below 160 degrees and the oil pressure is 35+ PSI. Thanks all. Peace. :cool: T-Bone.

ersatz928

Sounds normal to me. Oil pressure is dependant on Oil viscosity (related to temperature), engine RPM, and bearing clearances. Generally, as the oil warms up, viscosity lowers, and oil pressure drops. As long as you have at least 10 PSI at idle (hot), and about 20PSI or more at some RPM, you are OK.

wamara

Buckmaster, my oil pressure is very similar. This is a relief; I thought it might be too high!!

Black2001Z06

Cold Idle = about 60 PSI
Warm Idle = about 35 PSI

Running 5W30 Mobil 1. I've heard you want about 10 PSI for every 1,000 RPM, so theoretically, you could go down in the 10 - 15 PSI range at idle (I'd be a little nervous that low though).

Scruffy

When new, my car idled at 19-20 psi when oil temp reached 220+. It did this until I changed the oil (M1 5/30) & filter (AC Ultraguard) at 3,000 miles. Immediately after the change it now idles at 28-32 when hot. Belive it or not the pressure increased overall by about 10-12 psi across the board. I could never get a good explanation for this, but read here it was common with other forum members also. :confused:


[Modified by Scruffy, 4:46 PM 1/24/2002]

Jeff Jeff

T-Bone, my oil pressure behaves the same as yours. At 220 degrees oil temp I am at about 25 psi. I tried switching to 10w30, this increased the oil pressure when cold, but at high temp, it was still at 25psi.

Tom Burgess

cold idle: 44 psi
hot idle: 34 psi
cold 2000 rpm: 57 psi
hot 2000 rpm: 47 psi

I see 10 psi difference between hot and cold, cold being about 60F and hot 190F.

Tom