Oil Pressure Low - '05 GMC Sierra

[ShutUpHippie]

Hey guys! After quite the hiatus, I'm back from the Unemployed life...

Anyway, my question is this: My Pickup (2005 GMC Sierra, 5.3 V8) is having an issue with low oil pressure when starting cold. The lifters tick a little and then slowly the oil pressure reads normal after several miles at normal operating temperature.

Anyone have any ideas? I am thinking about trying some Auto RX http://www.auto-rx.com/ to see if there is some sludge gumming up my pump or sensor. Any help/ideas/experiences are greatly appreciated! Open to many things, would LOVE to do this on the cheap.


Thanks,
Rob :confused:

[Patrolman]

Change the oil? Make sure it is the right weight? Does it have enough oil? I would expect a couple seconds of lifter noise max so it can build some PSI. The oil PSI should actually be higher at cold temps. A couple of my older vehicles used to peg the oil PSI when it was cold and gradually come down as the engine warmed.

[ShutUpHippie]

Just got an oil change- full synthetic, correct weight. Fluid levels check out fine.

Bad oil pump or sending unit? I would guess that if it has a hard time pumping cold (thick) oil. I'm no mechanic, but I'm guessing the prognosis will not be very good. It doesn't do this EVERY time, probably about 50% at the moment. If I give it some RPMs while at a stop, the pressure will stay where it needs to be, but it's killing my MPGS :lmao:

[Patrolman]

I would personally put a mechanical oil PSI tester on the engine and test to make sure the gauge is reading right. My dads truck reads low, or near 0. He put a mechanical oil PSI gauge on it for a day or so, and it read with good PSI. Turns out the dash gauge is way off. You might get lucky, but the lifter noise sounds like maybe more.