2005 GMC C2500 Low oil pressure on cluster display

COLMHUR

MEMBER
2005 GMC C2500
V8
4WD
AUTOMATIC
60,000 MILES

I'm working on a 2005 GMC 2500HD with a 6 liter v8. I'm getting a Low oil pressure warning on the I/C display. I have checked the oil pressure with a manual gauge, and I'm getting 5 psi at idle. I have replace the oil pump, o-ring seal on pick up tube. I'm still getting the low oil pressure. I tried a new O/P sending unit, no change. Any ideas?

1 Reply

BRIAN 1

MECHANIC
1,030 POSTS

Check these things, If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions:
"� Oil pump worn or dirty

"� Refer to Oil Pump Cleaning and Inspection.

"� Oil pump-to-engine block bolts loose

"� Refer to Oil Pump, Screen and Crankshaft Oil Deflector Installation.

"� Oil pump screen loose, plugged, or damaged

"� Oil pump screen O-ring seal missing or damaged

"� Malfunctioning oil pump pressure relief valve

"� Excessive bearing clearance

"� Cracked, porous, or restricted oil galleries

"� Oil gallery plugs missing or incorrectly installed

"� Refer to Engine Block Plug Installation.

"� Broken valve lifters

"� Repair as necessary.

If the oil pressure reading on the J 21867, or equivalent, is within specifications, inspect for the following conditions:
"� Plugged or incorrect oil filter and/or malfunctioning oil bypass valve

"� Malfunctioning oil pressure gage or sensor

here is the oil pressure spec, Oil Pressure - Minimum - Hot 6 psig at 1,000 engine RPM

18 psig at 2,000 engine RPM

24 psig at 4,000 engine RPM
if all this checks good you might have a problem in the guage itself in the IPC. Post back with any other questions.