Oil pressure?

[gillguy]

I have a '07 Chevy Classic 2500HD w/DuraMax:D I have about 1100 miles on it and the oil pressure seems to be low. I plan on taking it to the dealer and have it checked, but I wanted to get more info first.
What should the oil pressure be?
My gauge goes 30/60/90/120
On start up in the morning the OP is at 90, after a few miles it will drop to around 60, this is running at 50-55MPH
In the afternoon I startup and the OP is just over 60, then while driving a few miles (5) at 50-55MPH it will drop to just above 30 maybe right at 40.
This is my first diesel so I'm not sure. I know my Chevy 350 has a higher OP than that and that's on the original 1988 motor.
So what oil pressure should I be seeing on my DuaMax?:confused:

Thanks
Bobby

[WILLYD-MAX]

Sounds normal. My 05 ran the same. Now the 07 Classic I am driving is the same way. Nothing to worry about.

[killerbee]

On start up in the morning the OP is at 90, after a few miles it will drop to around 60, this is running at 50-55MPH
In the afternoon I startup and the OP is just over 60, then while driving a few miles (5) at 50-55MPH it will drop to just above 30 maybe right at 40.
This is my first diesel so I'm not sure. I know my Chevy 350 has a higher OP than that and that's on the original 1988 motor.
So what oil pressure should I be seeing on my DuaMax?:confused:

Thanks
Bobby

Normal, only in the sense that all these trucks do the same thing. But not necesarily how it should be designed.

There is nothing dangerous about what you are seeing. The oil gets significantly hotter than the coolant it is interfaced with for cooling, when empty, that will be about 40 degrees hotter than the coolant, making the oil 240. Up to 260 or so in hot weather. (temps pre-cooler)

The steady reduction in pressure is strictly a function of the viscosity reduction as it heats, unless there is a foaming problem, not indicated.

Now the problem worstens when you tow. The harder you load it, the worse it gets. I have seen 20 psi at 2400 rpm, with oil at 350 degrees. This IS a problem. Flow rate is the same, but hydrodynamic lubrication suffers greatly at these non-design oil temperatures.

[JZ]

I have a new 07 LMM. Just took it in to be sure the lower OP was documented. The mechanic left the spec sheet in my truck when I picked it up. Minimum Hot at idle is listed as 14 psi. Minimum at 1800 RPM is listed as 42 psi. I'm over that but it still doesn't feel right when my 01 Duramax read almost twice what my 07 does at idle. From what the mechanic documented from the scan tool, I do also suspect my dash gage reads low. It's about time for me to get an updated scan tool so I can see it myself...

JZ