I have a 1 drip/sec oil leak with oil under pressure (seeps like shown when engine is off) and have tracked it to the right side where where the rear cover and oil pan come together:



I removed the lower transmission bolts and re-torqued the back 2 pan-to-block bolts and pan-to-rear cover bolts. All were loose. One of the pan-to-rear cover bolts was very loose; perhaps 1 to 2 full rotations.

I cleaned the area and still getting the leak. I can't tell if it's coming from the rear cover gasket, pan gasket, or both. 12 Nm seems really soft for those pan-to-rear cover bolts. Do you think I could add more torque? Also that lower right rear cover bolt (shown); I can't get my torque wrench on that bolt but I can put a close end wrench on it and perhaps tighten it further too; perhaps pulling the pan-to-rear cover bolts completely out first? Last thought; perhaps it's still leaking because it will take a while for the oil pan gasket to reseat after passing dirty oil (if it ever does)? Any other thoughts?

 

usually you have to apply a dab of sealant wherever 3 mating surfaces meet to void whats in the picture

 

Agreed; I have a feeling this has worn/broken down over time? The truck as 178k miles on it. I was wondering if putting heat in this area might not get it to reseat.

 

Why do gaskets leak?

Gaskets are required do their jobs inside of your engine, which is a pretty hostile place to work. Constant exposure to high temperatures, high pressures, vibrations and contact with hot fluids over a period of time will cause even the best gasket or seal to develop leaks.

 

Clsimmon I was reading your post and saw you UV oil leak issue an the right rear corner of the oil pan and thought back to last year when I had the same problem with my 08. I thought I would share this picture from last year and explain what I did.

I removed the trans bell housing bolts and cleaned the crap out of the oil pan to engine seam. Using a combination of dremel tool with wire brush and brake clean solvent I really made it spotless and made sure there was no oil residual and applied some Permatex 82194 Ultra Gray Rigid High-Torque RTV silicone around the area. Originally the oil would leak down the starter bolt closest to the block then drip on the trans cooler lines where the wind would blow it back onto the bottom of the bell housing. It took some time to find it but I finally did (doing the same thing you did). I debated on just pulling the pan and replacing the gasket but I had no other leaks so I used a trick that I had used in the past on an old transfer case that had a leak at the seem and so far (knock on wood) its holding up just fine. Here's a pic, It's not pretty but so far a year later not a drop.

 

Really good post! I wish I saw it about 4 hours earlier when I had the starter off I resolved that I'd just replace the oil pan gasket at a later date and just keep refilling the oil. I would go back and do this but honestly the starter wasn't all that easy to get back in. Ensuring that wiring harness was routed correctly and attaching the positive and starter lead under the truck wasn't easy.

 

20yr old gasket leaking, time to replace! Get a quality gasket and replace, Done! Cheap fix to stay in the H2 or you can give in, and spend an extra $80k+ for a comparable replacement to the 2?

 

No doubt the correct and best solution to a leaky oil pan gasket is to replace it. Considering its not going to be a quick fix and a number of things must be removed to get the pan down if you have no other leaks around the base of the pan and you can get away with the quick fix why not try it.

Also something else to check while your at it is the PCV valve which on the L92 is not a valve at all but something that resembles a stardard PCV buts thats it. It has no *****, springs or anything else inside of it but a tiny whole that is under 1/8 inch in size that can get plugged. Once that happens the engine crankcase pressure will build and cause oil to be force out anyplace where there is a weak or worn out gasket.

There is no need to replace it, just remove it and clean the inside of it, I used some brake clean solvent and a rifle bore brush on a drill to clean it up. At the same time I found a small crack on the rubber hose that connects it to the plastic line that runs back to the intake. As these trucks and SUV's get older you can expect this stuff to deteriorate and need attention and replacement.

 

Here is another interesting discovery I stumbled across about the GM factory LS oil pan gasket. It has seam in the metal where it is joined together and exactly where the leak seems to happen.
This seam or joiner does not exist on the Felpro replacement and all the guys on the LS forums recommend the use of the Felpro gaskets over the GM ones, not surprising and what I will use if the leak should start again.

 

Good info! The way the block, pan and rear cover all come together at this corner while two huge tranny bolts can easily hang down on the pan, i'm not convinced this was the best design.