Duramax oil pressure question
 

Rode in my friend's 2006 GMC Duramax pickup today. Oil pressure gauge shows 0-120. Start up pressure was 60. After warmed up, pressure at 60mph was 30 lbs, sometimes 25. No higher than 30psi with high rpm's taking off from a stop. Idle pressure showed around 5psi. I didn't say anything but this seemed low to me. Anyone know if these are appropriate pressures on a Duramax? My intuition was that these pressures seem low and if it were mine, I'd confirm the gauge was accurate and if so find out why the pressure was low.

My questions would be:

Is this a factory gauge?
How accurate is it?

I tend to fall back on the old Smokey Yunick philosophy of 10#/1000RPM being adequate.

Did some googling. Those pressures may not be out of line for a Duramax.

I do know earlier engines suffered fuel in the lub' oil....that would reduce overall oil pressure.
Oil Pressure - Minimum- Hot - at idle 14 psi..( 12 to 15psi.)..Oil Pressure - Minimum - 1800 RPM 42 psi.

Oil grade will make a slight difference like maybe a 10W something. The factory gauge is not accurate to rely on and oil pressure should be checked with a scanner.

Leaking injectors will slowly reduce oil pressure. Test oil quality with a Blackstone kit.Blackstone Labs



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Normal.

My 06 Duramax shows the same. I'm running Rotella t6.

Yeah...but what does the scanner read out say ?

This is lifted from Bulletin for '07 and up so may not apply. .................


"......If the oil pressure is 8 PSI or higher do not attempt engine or gauge repairs.

If oil pressure is below 8 PSI, continue with the SI diagnostics for low oil pressure, and make necessary repairs.

Note: The instrument panel gauge is buffered. The actual reading taken with the mechanical gauge may not correspond with what is seen on the instrument panel gauge. Rely on only the mechanical oil pressure gauge for this diagnosis......"




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Gm gauges for these trucks are not accurate... At least coolant.

Work on quite a few, and have seen coolant temp on scan tool at 190f , but it was at bit over 210 on dash gauge. One extreme example. However seen 10 f lots of time.

No idea on oil pressure gauge accuracy. It is pretty normal to see after hard run on interstate the OP gauge showing close to red bars. (5-10)

GM trucks etc have had gauge cluster issues since about 2001 or so.my 05 the temp gauge rolled around to 100 and stayed my gas gauge was off 1/4 tank and the volt meter was 4 volts low.