Oil leaks on Chevy LS engines

[Snagglefoot]

Chevy LS engines are generally great for not having oil leaks. Mine is a 6.0 in a GMT 900 Burb. It has 260,000 miles. After about 200,000 miles it has a bit of oil leakage.The first photo shoes some oil accumulating at the bottom of the pan in the area between the fill plug and the oil filter. There are no leaks at the oil filter itself. This’s a straight up view underneath the oil pan.

 

[redhat]

If you remove that inspection cover on the trans. bell housing, is there oil in there? Could be rear main, or the rear cover leaking.

Is the area where your oil cooler lines or blockoff plate mount to the side of the pan dry? If no, could need a new oil cooler gasket.

 

[Brian123]

What oil have you been using and have you looked at the PCV?

 

[oldhp]

Clean it all off first. Have you ever replaced the drain plug? It has a built in seal, maybe it's worn enough to leak? Rear main? Oil pan rails?

 

[Snagglefoot]

The next photo shows where the transmission is bolted to the engine. There looks to be a small port. ( Circled with in red). Would that let out oil from a rear seal leak?

 

[Snagglefoot]

Here is one showing the dry oil cooler lines but I noticed this droplet of oil forming, circled in red. I’ll take a close look at this.

 

[redhat]

Clean it all off first. Have you ever replaced the drain plug? It has a built in seal, maybe it's worn enough to leak? Rear main? Oil pan rails?

Good first steps, clean it off and check the drain plug seal.

Yes, oil can seep out of that hole.

 

[Snagglefoot]

What oil have you been using and have you looked at the PCV?

I got about 200,000 miles using 5w30 synthetic. Currently I’m using Euro 5w40. The oil leakage developed while still using 5w30.

 

[Snagglefoot]

If you remove that inspection cover on the trans. bell housing, is there oil in there? Could be rear main, or the rear cover leaking.

Is the area where your oil cooler lines or blockoff plate mount to the side of the pan dry? If no, could need a new oil cooler gasket.

I’ll look for the plate.Thanks.

 

[Alex_V]

I haven't seen a truly high number of vehicles meeting this criteria so it's more of a casual observation, but the rear main seal seems to have a much higher rate of starting to leak above 250K.

 

[Snagglefoot]

Clean it all off first. Have you ever replaced the drain plug? It has a built in seal, maybe it's worn enough to leak? Rear main? Oil pan rails?

I don't get a drip at the plug, but I’ll watch. Notice it is in the side and not the bottom, so a drip should form I would think, but I’ll clean it and check. I am planning on dropping the pan in May to replace the Oil pump O ring so maybe I’ll learn something.

 

[dumkid]

Oil pressure sensor leak? It's directly above the bell housing

 

[Snagglefoot]

Oil pressure sensor leak? It's directly above the bell housing

Good point. I watched a You Tube video of two mechanics preparing to drop the transmission to replace a main seal. It was a 4 wheel drive and they had to drop the transfer case first. When they dropped the transmission, the look on their faces was priceless. The leak was from the pressure sensor. I will check.

 

[jhs914]

Good point. I watched a You Tube video of two mechanics preparing to drop the transmission to replace a main seal. It was a 4 wheel drive and they had to drop the transfer case first. When they dropped the transmission, the look on their faces was priceless. The leak was from the pressure sensor. I will check.

Link?

 

[Snagglefoot]

Here is one showing the dry oil cooler lines but I noticed this droplet of oil forming, circled in red. I’ll take a close look at this.

View attachment 212877

Correction, those are dry transmission cooler lines. I have more photos to come as soon as they download from the cloud.

 

[Snagglefoot]

Thanks everyone for your attention and helpful suggestions. More photos coming tonight.

 

[Snagglefoot]

Link?

Looks like I imagined the look on their faces, but you can imagine what expression they might have had. They found the leak at 17:14. There may have been a rear seal leak as well but I'll bet a lot of the oil dripping on the ground was from the pressure sensor and possibly the cam sensor. They changed the rear seal anyway after installing new sensors.

 

[Snagglefoot]

Oil pressure sensor leak? It's directly above the bell housing

Have a look at posting #14 where they found that to be one of the problems. (but only after removing the driveshaft, transfer case, transmission and flex plate.

 

[Snagglefoot]

I have more photos loaded. This group focuses on the oil cooler block that is bolted to the block. There is definitely is one leak there.

 

[Snagglefoot]

The next two shots focus on looking at the oil pressure sensor with my remote camera. It seems clean but I can’t quite reach the base of it. In any case, there’s does not seem to be any oil high up on the bellhousjng.