On cold start up, oil pressure rises to about 45 pounds, then drops in a few minutes when it gets warmed up to about 20 pounds at idle.

Cruising it rises to around 30-35-40 pounds, depending how much throttle I'm applying. I think at WOT its around 45 pounds.

Yesterday when I was cruising, at idle the car was only pulling around 18 pounds at idle, and oil pressure rising a little more sluggishly when cruising?

Some sort of oil sending problem causing this? The only leak I have is the rear main seal, it could use replacing. Oil pan gasket and timing chain gasket were replaced about 2 months ago, things were fine after that. Intake manifold is clear of leaks too.

Thanks for any help!

 

Sounds normal to me. When a car is just warming up the oil pressure is going to be higher...as it gets up to running temp and as the oil heats up it looses some viscosity causing the pressure to drop off some. Also When cruising 35 to 40 is about right. (depending on the gear and rpms) I don't think you have a problem.

 

I had that problem on a mustang I used to have, if you messed with the wire at the sender the oil pressure would come up. So checking the sender is worth a try.

 

if that pressure is normal, is mine not right? mine at hot idle has about 35, and at 2k in 6th has 60...its a 95 6 speed, 130k on motor, doesnt burn oil

 

On the highway 70mph 6th gear I'm at 35. Just about 20lbs for every 1000rpm is about what you should be IMO.

 

so is it good or bad that i have more pressure than normal?

 

I don't see a problem with higher oil pressure. What oil are you running?

 

I am in the same boat as you. If you don't want it to go down so much use 10w30 do alliviate the problem of thinning out over time.

 

when the oil is cold it has more viscosity (like someone said) and tends to be thicker when the engine warms up the oil thins out and is low in viscosity which makes the pressure drop. at idle the pressure guage may show one thing but as throttle is increased the pressure reading rises simply b/c the pressure in the crankcase is increased. this is completely normal and is part of the reason why it is better to run 5w30 in the winter and 10w30 in the summer...HTH!

 

im running castrol 10w-30

 

GM says oil pressure at idle should be something like 7 psi or better and then 10psi per 1000 rpms.

 

Thanks guys, I'm gonna try a few things with the oil cooler, sender, and double check what the pressure should be, if it says in the Haynes Manual.

 

those numbers sound right to me. I totally cleaned out my cooler today but it really didnt help much. I here removing it will give you around a 10 PSI increase, and by the way the cooler really doesnt help at all, allot of camaros didnt even come with em, they were dealership upgrade.

 

Where is the oil cooler? I don't think I've ever seen it, I'll probably go look at my Haynes manual. Yeah, some Z06 owner friends of mine told me under 20 pounds is bad.

 

According to my sources, your oil pressure is spot-on. According to Lingenfelter's book, any small block chevy with a functioning lubrication system will get about 5-10 psi per 1000 rpms. Higher oil pressure is not necessarily better, nor does it mean more oil FLOW, it really just means that the oil pump has to work harder because the oil is more viscous. REALLY HIGH oil pressure is not a good thing performance wise since you are losing more power parasitically to spin the pump.

And yes, I agree with the others, it comes down after a while, after the oil heats up, because it thins out due to temperature.