Did my regular oil/ filter change, first drive after this got a PO521 code. Oil pressure sending unit and my oil pressure gauge was on zero. Cleared the code and pressure gauge went to max a couple seconds then back to zero & triggered code again.
double checked oil level, it was good. No oil leaks under truck. Pretty sure I actually do have oil pressure since I had to drive about 20 miles and there was no tappet sounds, truck ran fine, engine temp stayed normal.
Just cant figure how changing the oil / filter could cause the sending unit to fail!
This is a 2007 silverado LT with the 5.3 engine & 264K miles on it. Anyone ever have this happen?
stupid sensor is behind the intake manifold on these but looks like I can swap it with the right swivles and extensions.

 

Well first let me say in spite of the you tube videos unless you have hands the size of a five year old changing the oil pressure switch without pulling the intake is pretty much inpossible no matter how many extensions and swivles you have! So removed the intake, time consuming but made changing the oil pressure switch and filter screen very easy. Reinstalled intake with new gaskets and tourged to spec. After finishing the oil pressure gauge worked fine again, 2007 silverado 5.3 ran fine but had 2 glitches one I would get an occasional random service engine light. Always same two codes 1. Left bank lean and 2. Right bank lean. In addition I would get traction control off / service traction control usually when I braked to a stop. This would self clear as soon as I accelerated. Long story short, disscovered the vacumme line from the PVC to the engine nipple had a very slight vacumme leak. The hose had a 1/4" crack at the bottom though it still felt tight when you slipped it onto the nipple. Fixed by wrapping duct tape around the cracked hose and using a hose clamp to secure it to the nipple. Now service engine codes and stabiltrack notices are gone & have not returned. Just posting to maybe help anyone dealing with these issues.

 

I've got an oil pressure switch to replace on my 2006 Silverado 4.8, and had watched those same videos I suppose, and planned to look at it this week. Haven't looked at it to see how hard it was to get my hands on it back there. Since I also need to replace a knock sensor, I'll just wait until ready to pull the intake and get both.

 

Did one on a 2008 Tahoe years ago without removing intake .Need the right socket and extensions and it wasn't too bad. Repair shop of course wanted to remove intake to the tune of $400+.There has been a lot of discussion about this on this site in the past.