How to Find and Fix a Rear Engine Oil Leak: Yukon / Tahoe / Silverado / Sierra / Suburban

In this video I show how to locate and repair an oil leak that looks like it's coming from between the rear of an LS engine and the front of its automatic transmission. In this case, this truck had leaking oil cooler lines and I show how to replace the oil cooler line / block-off plate gasket.

NOTE: I do not recommend buying Fel-Pro Gaskets if you have oil cooler lines as the Fel-Pro Gaskets are prone to start leaking prematurely.

To purchase a genuine GM Gasket, click one of the following link:

I am an Amazon Associate and earn a very, very small commission on any sales made at the above links. The price is the same whether you use these links or not, but these links do help support my family. Thank you!

[alexcharow]

Do this first. Just snug up the 2 bolts with a 10 mm wrench. Wipe it down to get any oil off. If it still leaks after a week. Then replace the seal.

[doncallicott]

Great video and informative. Blessings on raising those children on the farm.

[matthew]

Well no wonder. I had already replaced this once and the dumbass at the counter gave me the block off plate and I have Cooling lines. This helps a lot. I ordered the correct one from your link and will change it next oil change. Small leak is fine for now lol

[garrettwalker]

Thanks for the video. Hopefully this is the problem I’m having my 2014 Escalade. Congratulations on the property and may God bless you and your family

[pianodude]

I had a similar issue. However, the culprit was the oil pressure sensor. It was coming loose and oil was seeping out. I replaced it and tightened it and no more oil leaks!

[ScarabChris]

Great video! I have a 2008 Escalade EXT 6.2 all wheel drive. It leaks oil, I estimate maybe a half tea spoon in a 24-48 hour period based on what I see on the driveway, also depending on how much driving I did. I was thinking the most common problem, rear crank seal. But then I learned about that inspection cover. My oil leak is coming from higher up, above the oil filter. The underside of my truck is identical to yours. I see no oil at all when looking at the engine from under the hood so not a valve cover so I suspect the oil cooler lines now as well. I will jack it up this weekend for a closer look. EDIT..Yes my truck has the full tow package and I do tow a 7, 000 pound trailer 4-5 times a year and it does leak more oil when I tow.

[dailys]

My 09 Silverado looks identical as far as the leaks go. I’ve been messing with it the last couple days trying to find the leak. I was thinking rear main when I saw the oil accumulated around the trans inspec plate but after popping it off everything is dry inside. The oil seems to start at that gasket. I’ll be ordering one now. Thanks!!!

[jhtubevids]

So do you have an update? Did this fix your leak. I have 2009 esv and when i looked the other day it looked 💯 like your did and i was suspect of this same block but i didn't know what it was

[alonsoamezcua]

Currently have the same issue last week did my oil change noticed a lot of oil leaking from over the oil filter cleaned it all up finished my oil change drove it and now looks exactly like your video. Haven't checks the inspection cover, hoping it's the oil cooler line gasket.

[MUCKFOOT]

mine was leaking from the canooter valve.

[OfficialLOW]

The cooler doesn’t have any coolant lines going to it? Most Benz and bmw do is why I ask

[melissaholden]

I had a similar issue found the bolts loose on the plate under the intake plenum that the oil pressure sensor screws into. 5.3 has cylinder shutdown solenoid under the plate vibration loosens plate bolts

[thomastaddeo]

What are those lines next to the inspection window ?

[wyomingadventures]

Nice to see someone else keeps things clean under the hood. Very interesting to see the newer Ls engine. How do get the oil filter off? It looks tight around there. My old pickup oil filter is hard to get around the filter so I use a special tool to get to it. I do believe in using Original manufacturing parts. Great job with the video!❤🐥🦆🚘😊

[thesetruths]

I have a 2005 Yukon 5.3L 4x4. Looks exactly the same. I may have a very slow rear main leak. I just got it and am watching it now after a fresh oil change. Has 216, 000 miles on it. Seems to run great though.

3 questions:

1. Was there a cover on your inspection hole that shows the bottom of the flex plate? Mine does not have a cover of any type. I can see the bottom of the flex plate.

2. I have a pair of ramps that raises vehicles back or front tires by about 12". Would that be helpful to use for this job?

3. So the rear seal has two parts? A shaft seal, plus a shaft seal cover gasket? If the cover plate gasket leaks, where is that oil coming from, the rear main seal that's leaking? Why is there cover plate gasket to begin with, to keep the seal/crank area as clean as possible?

Thanks!

[massachusettsprepper]

Yes sir my friend the power of deduction and then getting it fixed. Thanks for sharing.👍

[DanielDaniel]

Man I thought my rear main was leaking too on my 11 denali but it sure is my oil cooler lines. They're really seeping bad at the radiator side hose crimps

[macstallyon]

Will a bad oil sender unit cause oil to be inside the inspection plate?? I’m loosing a quart a day and it says it the oil sending unit but the oil seems to be dripping around and out of that hole

[kennethporth]

How yo check fluids and grease and oil on y con 2004

[womanswrench]

the amount of pure envy that is coursing through my entire being over how you so obviously do not live in the rust belt & how beautiful & well maintained your undercarriage is & that you’re actually able to dutifully maintain it - is not ok !

but anyway - thanks for this video. have been dealing with this leak for 2 weeks now in the same exact area. i checked my rear main via the inspection cap 2 weeks ago when this started…. id recently put my valve body4 back in after id rebuilt it & likewise - it was dry. used the uv dye - wasn’t all that helpful…so i am actually finally able to get under my yuk, replace this & hopefully put an end to it. hopefully. otherwise - this is probably something much more of a PITA & a definite day ruiner.