LaMarCalvert

Jibe - I work for GM, so I have access to all the Service Manual information for ALL years. There are lots of exploded parts diagrams, listed by RPO code, so once I found the RPO code sticker in my son's truck, it was clear what I was working with. If you need something particular, I should be able to help you out.

SOLVED: Update to this issue - Valley pan cover was the culprit! All the "You-Tube sleuthing" watching the various videos on this topic did help a lot, but caused a lot of confusion, until I went to the GM OEM information. The RPO code is LC9, so I obtained the exploded parts diagram, and found that this engine has cylinder deactivation solenoids under the valley cover, and NOT knock sensors on the top of the valley cover. Had my son order oil pressure sensor, filter, cam sensor, intake gasket, and valve cover gaskets from RockAuto.com. Parts arrived in 2 days! Removed the intake manifold, and found the root cause almost immediately! OF the 11 bolts holding the valley pan cover in place, 8 were finger loose! Also, no evidence of any threadlocker ever being on the bolt threads. Also, there was no cam sensor next to the oil pressure sensor; there was the connector for the cylinder deactivation solenoids only. Everything was cleaned up nice, and as an added measure, I added a very light film of RTV to the Valley pan mounting area and the valve cover mounting areas, just to give a little hold for the gaskets. OEM instructions say not to, but after following the OEM directions on my transmission pan gasket, this was the way to go. Not good gobs, or even a small bead - just used my fingertip to lightly coat the sealing area. Also, used high strength removable threadlocker (Permatex - orange bottle) on the valley pan cover bolts. I installed the intake manifold gasket dry, as the OEM recommended. Started teardown and completed repair on Saturday, thanks to the RockAuto parts arriving one hour after I had cleaned everything up from teardown. Also, did this in 35 degree weather in my driveway. Truck now has no leaks! I think all the oil leakage contaminated the MAF sensor (intake had oil in it near the throttle body), and he had a bad oxygen sensor - Got a check Engine light on start-up. Replaced both, and truck running good as new. Hopefully, this information will help somebody else out, as I have spent about 6 - 7 weeks working on this truck (in between working and day-to-day life), and was ready to call an audible, lol! One last note - when we did the rear main seal repair, we found several of the 12 mounting bolts for that cover were finger loose as well. We used threadlocker here as well.

Mike - Yes, 100% certain that is engine oil. So...last night, I tried to use the "My Lizard Cam" to see back there where the oil pressure sensor is located, and observe while running. Like txab said, I am certain this is a leak under pressure, as it did not start leaking immediately upon start-up, but soon after. It is very oily back there, but could not see the steady stream I was seeing under the truck. Also, was able to squeeze my hand back there, and wiped all around the base of the oil pressure sensor, and it is actually dry there...there is oily buildup on that surface just below the sensor on the back of the block...where it bolts to the transmission. With the fact that I now know that intake is dry, I am going to follow Mike's advice, and take the upper intake manifold off, to hopefully see better. It now seems to point to the cam sensor. I want to try to uv dye in the oil before tearing into again, in the hopes of helping point out the source. Anyone had any luck with a particular brand/kit? (I tried this years ago, and maybe it was inexperience back then, but I do not recall being able to see the uv dye using the "special" glasses and light. Maybe it was the product I was using) In any event, Thanks Gentlemen for the advice on this. I will continue to post updates, as this has been a learning experience, and have no problem sharing the solution.

I have this little inspection camera with a small display - gonna try to view the pressure switch with this, and hopefully this is the culprit! I will post an update either way, once I get this figured out.

I got a response from you - txab via email, but it doesn't show up here - you asked if I checked the oil cooler attachment at the block - where doe the oil cooler lines connect to the block? I have to get back under there, but I was assuming they are attached somewhere near the oil filter housing, and the leak is not coming from that are. Appreciate the responses txab!

Good morning All! Looking for some help for my son's 2012 Silverado, 4WD, 5.3L. I have attached a video of a pretty bad oil leak my son has on hi truck. Video is BEFORE any repairs were attempted. 1. Son thought it was the oil pan gasket, so he went through the process of removing front differential, and other parts to perform repair. Halfway through disassembly he realized it was NOT the oil pan. 2. He then thought it was the rear main oil seal, so he put truck back together, and had it towed to my house. I spent the last 3 weekends figuring out howto, and then replacing the rear main cover/seal. 3. Started truck and still $%%& leaking! Son shared this video with me, and I viewed it several times now, and based on what I saw under the truck and the video, this looks like the oil pressure sender, or something up higher. It is clear to me now that we worked on the wrong thing! I am about ready to pull all the remaining hair out my head on this, and was hoping someone could view the video and give their thoughts? Is it the pressure sending unit, or possibly a valve cover (I doubt this, but possible), or intake gasket? It is now below freezing in Michigan, and I do not have this truck in the garage (I WAS in the middle of my rebuild on my 1985 Camaro, so I have no room, and need to get this truck fixed, or towed to a shop if it out of my abilities). IMG_52921.3gp