2006 GMC Sierra - Low Oil Pressure

[Sam Hutson]

My son's 2006 Sierra 5.3L Z71 4x4 started showing "Low Oil Pressure" at start up and the gauge will read low for a moment.  Once it's started for a few seconds, the gauge moves up, alert message goes away.  Truck runs fine.  If it's restarted after warmed, it will not read.  Oil level is normal, oil is clean and almost newly changed.  Suggestions?  Recommendations?  I'm no expert at working on vehicles but can do most simple-medium tasks.

[richard wysong]

did this start right after the oil change? its possible the oil filter is draining over night. or maybe wrong viscosity of oil if so

[Sam Hutson]

It's a fairly new to him truck, with a new change by the dealer.  Oil looks new, so I believe it was recently changed.  I'm going to change it myself and see if that matters.

[richard wysong]

if it just stays on for a second or 2 on a cold start its normal. over night the oil drains from all the passages and it takes a second for the oil pump to refill them and build pressure to shut the light off. changing the oil again can't hurt just to make sure . use name brand oil and filter tho

[CamGTP]

Changing the oil won't make a difference, just change the filter to rule that out.

 

Doesn't matter if it's 5W20, 5W30 or even 10W30, it's going to build oil pressure very quickly when it's cold if the filter is working right. As well as if the oil pick-up tube o-ring is in good condition.

[Supreme Pizza]

Pickup tube o-ring is bad. The oil leaks through the seal over night and results in low oil pressure on start up. The oil pump doesn't pump air very well. The longer the truck sits, the worse the problem gets. Let it sit for 3 days and you will see what I mean. Let it sit for 5 minutes, and no problem at all. Parking nose up hill or nose down hill, adding an extra quart of oil, etc etc, lots of ways to confirm the diagnosis.  When you change the o-ring, do it through the timing chain cover, and use the opposite bolt hole for the tube upon reassembly, with an aftermarket tube retaining bracket. MUST get the correct puller for the crank pulley. Once you reinstall the timing cover, start the engine to confirm that there is oil pressure. Then let it sit for a day or two and restart it again to confirm that its fixed before you reinstall the water pump. Replace the front seal while your in there. Have a nice day.