LH6 5.3 Intermittent Low Oil Pressure

[Matthew Cleaver]

Hi everyone. It’s my first time here but I need some help. My 2007 Silverado with an LH6 5.3 DOD motor has intermittent oil pressure issues. Alittle back story, the truck has 274k on the original motor. Recently, I replace the valley plate gasket, but only the outer part. For convenience sake, I left the DOD tower gasket part. After that, I replaced the oil pickup tube o ring and gave the truck a full service. My issue now is, I still have intermittent low oil pressure. I’ve read about a service bulletin where the oil pressure relief valve sticks, which requires replacing the oil pump and such but there are so many possibilities I’m not sure what to pursue. I know the oil pressure sensor is good and the screen below it is clean. The issue happens randomly. I can start the truck and it will idle and warm up fine (maybe slightly lower than usual) and then I can drive it. I’ll be sitting at a light or a stop and I can slowly watch the oil pressure fall off. Sometimes even while driving slow and then the oil pressure stays low or 0. It doesn’t cause any bad noises that I know of because I shut it off immediately but I’m so confused. After letting it sit for a bit and starting it up it’s fine. I’ve heard many possibility between it being the oil relief in the pump, the oil relief in the pan that apparently exists, DOD lifter problems (although they aren’t giving me any bad noise) leaking DOD valley gaskets (the ones I skimped on replacing) and more. I’m lost as to what to do. Can anyone offer some insight?