GM Service Manual Online
For 1990-2009 cars only

Low or No Oil Pressure

The following can cause low or no oil pressure:

    â€¢ Low oil level -- fill to the full mark on the oil level indicator.
    â€¢ Slow idle speed
    â€¢ Incorrect or malfunctioning oil pressure switch -- replace the oil pressure switch.
    â€¢ Incorrect or malfunctioning oil pressure gage -- replace the oil pressure gage.
    â€¢ Improper oil viscosity or diluted oil
       - Install oil of proper viscosity for expected temperature.
       - Install new oil if it is diluted.
    â€¢ The oil pump is worn or dirty -- clean or replace the oil pump.
    â€¢ The oil filter is plugged -- replace the oil filter.
    â€¢ The oil pickup screen is loose or plugged -- replace the oil pickup screen.
    â€¢ A hole in the oil pickup tube -- replace the oil pickup tube.
    â€¢ Excessive bearing clearance -- replace the bearings.
    â€¢ Cracked, porous, or plugged oil galleries -- repair or replace the engine block.
    â€¢ The gallery plugs are missing or improperly installed -- install or repair as necessary.
    â€¢ The pressure regulator valve is stuck.
       - Check the pressure regulator valve for sticking in the bore.
       - Check the bore for scoring and burrs.
    â€¢ The camshaft is worn or poorly machined -- replace the camshaft.
    â€¢ Worn valve guides -- repair as needed.