5.3 low oil pressure

[RBUser]

I really appreciate your responses, so THANK YOU!!

I found the paperwork for the service where the Seller's dealership had performed the oil pan gasket replacement. Not sure why it never made it into the CarFax maintenance reports, but at least I did have the hard copies of it. Anyway, I thought I'd seen that they'd done the work on cleaning out the pan and replacing the o-ring, but according to that paperwork, it only states that there was an oil leak and that they fixed it by replacing the gaskets.

So now I'm planning on hitting those oil pan component issues next.

I still have yet to get the new connector (with pigtail) installed due to the difficulty accessing it. See photo:

 

[GM SUVer]

The screen is for the AFM engines, so it won't be on a pre-'07. The AFM system is really sensitive to sludge/gunk, so it has a screen at the point where oil is fed to it. If it's getting clogged, you're either running crap oil, running it for too long or your engine has sludge/gunk/crud that is incrementally working loose or all of the above. Removing the screen will allow any particulates to reach the tiny passages in the AFM system, potentially causing a much more serious failure. Don't remove that screen. Clean or replace it.

It could be the oil's viscosity drastically changing from temperature. Long trips and higher loads will increase engine operating temps and, therefore, engine oil temps. Synthetic oil is more stable at holding its viscosity, so that might help. What you might have is a split O-ring in the pickup tube. Thermal expansion coupled with wildly varying oil viscosity could be why this is an intermittent issue.

Next time it happens, with the vehicle parked on a level surface, be sure the oil level is at the "full" mark on the dipstick. Add two quarts of oil and park it with the front of your Tahoe in a nosedive, like pulling forward into a ditch or reversing onto a hill. See if the oil pressure suddenly climbs back to normal range. Drive back to level ground and rev the engine to around 1500 RPM and see if the low oil pressure returns. If so, it's gotta be a leaking pickup tube O-ring. Drain the extra two quarts and plan out the repair.

Also, if sludge, etc. is a factor in your engine, you don't wanna run any harsh detergents to quickly break it up and flush it out. The chemicals breaking up the deposits in larger chunks can cause more problems since these larger particles are circulating through the system. They can clog the screen and/or the filter and/or the lifters, etc. You need to slowly and gradually dissolve the deposits so they're removed during a routing oil change. The mild additives and detergents in quality oil does this. I highly recommend synthetic oil if you don't already run it. It might seem more expensive up front, but you can run it twice as long and it retains its operational and protective properties for much longer than conventional. Now, if your engine is, in fact, dirty on the inside, then I'd suggest running a quality cheaper conventional oil and changing it when it gets dirty, regardless of the mileage. ALWAYS use a good filter. You might end up changing it every 2-3K. But, it should start to go longer and longer before it turns really dark. That's the stuff being dissolved, suspended and then drained in the oil, cleaning out your engine.

I had a 2008 Yukon that had low oil pressure. Mechanic finally pulled the oil pan and replaced the orifice that is about a $10 part. I never had another problem with oil pressure after that.

 

[iboughtatahoe23]

I have a 2007 Chevy Tahoe LT 2wd with the 5.3 flex fuel. The day I bought her (April of 2016) I was 2 hours into the 4 hour trip back home when the "low oil pressure shut down engine" came on. Of course I panicked and pulled off, checked oil level, called the guy I bought it from, and prepared for the worst possible news. He assured me it still had pressure but just needed a new sensor.... Cut to pulling into my driveway.... Bought a new switch, the 1-1/16" socket to turn it, and built the perfect dual 6" + swivel tool combo to get to the damn thing. Swapped it out (took me close to 1.5 hours) drove around the block and same light comes right back on.... #&$@! Phoned a knowledgeable friend who told me most people forget or don't realise there's a screen under the sensor.... Well shoot, my new unit didn't come with one so I guess I'll go buy one, replaced the screen and oil pressure was good for another 1-2 months.... Yup, it F#&$ING happened again but this time while towing a trailer to a different state.... So knowing that my sensor was good and the screen was pretty fresh still I took it to whatever local jiffy lube was near and asked them to do a flush treatment (motor medic or something like that) and since that day I have never experienced low pressure again. Until new years eve a few days ago while completely loaded and heading to an out of town gig. I pulled over, checked oil, waiting around for my heart to mend and the engine to cool and started her up and oil pressure came back. Dropped a few more times there and one more time on the way home. Going to go through the motions again today and run motor medic, change oil, swap in a new pressure sensor, and replace the screen. I'm half tempted to remove the screen altogether although I'm not sure if that would cause a leak or do some sort of damage although I've since helped friends replace their sensors and found they don't have a screen (older models). Hope this helps someone. Sorry for the novel. I'll attempt to update in the following weeks as to whether it worked again or not.

HI I’m also having this issue in my 2014 Tahoe lt 4wd. I get 17 psi at idle and barely make 20 at 1000 rpm.

 

[OR VietVet]

HI I’m also having this issue in my 2104 Tahoe lt 4wd. I get 17 psi at idle and barely make 20 at 1000 rpm.

Screen in the oil sensor line?