I have a question about oil pressure. When my truck is idling I have approx. 25 psi of oil pressure but when I get on the road it jumps up to 65psi or better. Is this common or do I have something I should be concerned about? What does your truck idle at?

You didn't indicate the year of your engine. The Duramax oil pressure was reduced with the 2003 model year. My 2003 LB7 with 5w-40 Rotella Syn normally runs, at 2000 rpm or so, at about 60 psi warm, almost 90 if cold. At warm idle, it runs a bit under 30 psi.

It is a '02 LB7.

I see 35lbs at idle and 65 to 70 lbs at 2000 rpms.
Looks normal and nothing to worry about.

I only see 20lbs sometimes 18-19lbs tried all the oils (devlac,delo,rotella). When driving though I get 60-65lbs. Using 15-40 rotella right now.

I know that mine jumps around a little but I didn't remeber it seeming to move that much. I kind of figure it would be ok but though I would check. Thanks again.

Mine will run about 30 at idle. About 80+ when cold and 60 when cruising at operating tempeature running 2000 RPM.

It's normal for the LB7 oiling system.

Mine runs about 25lbs at idle to 65 lbs at 1850 hot.

Most engines with good gauges will show pressure swings. With electric gauges, those swings can be damped out.

I had a 1968 GTO with Autometer gauges and 1/8" tubing that would swing like the tach when I blipped the throttle.

At a cold start it pushes up towards 80 until it warms up then backs down to 30 and normally hits about 60-65 on the highway.

Mine the same as everyone elses

Mine Holds About 85-90psi Cold And When Hot A Shade Below 30 Psi. Thats Using 15-40 Rotella

Mine seems to be in the same boat. But I have a question,

K1XV, how do they lower the oil pressure? And if that is the case, why do the 03's have a guage that will read to 120psi? I'm not trying to be a smarta$$ just wondering why they would lower the pressure and install a guage that reads higher??

Mine seems to be in the same boat. But I have a question,

K1XV, how do they lower the oil pressure? And if that is the case, why do the 03's have a guage that will read to 120psi? I'm not trying to be a smarta$$ just wondering why they would lower the pressure and install a guage that reads higher?? ==========
I don't know specifically with the Duramax oil pump, but most oil pumps I am familiar with have a relief valve held closed by a spring, and by changing the spring stiffness changes when the relief valve opens.

As for the gauge that reads higher, I suspect the reason that range is used is to have a gauge that reads straight up when things are normal, so you could tell at a glance if any reading on the gauges was out of normal range. Long ago, I used to race in Sports Car Club of America, and we used to mount gauges and instruments so that the "normal" reading was straight up pointing at the 12 o clock position.

Besides, on the oil gauge, as others have reported, pressures up to 90 psi are regularly encountered with a cold engine, so a 120 psi gauge is not outlandish.

On the other hand, I have a 1980s Mercedes diesel car, and under normal driving, the oil pressure gauge is pinned at the maximum (3 bar, or about 45 psi). People unfamiliar with this look at the gauge and worry that something is wrong. Just a different philosophy on how a gauge should read, I guess.