Oil leak

[Rocket Man]

Yes the cover seal was too, I think. It was a few years ago. Dorman one I got was crap. Returned it and got a NAPA one.

Don’t ever put any Dorman part in a place that’s hard to get to, definitely not in an area that requires the transmission to be pulled to get to it. OEM is the way to go in those cases. I used ACDelco for my rear seal and rear cover. I did mine as preventive maintenance when my trans was out, and it had lasted 160k. I don’t ever want to do it again and figure the new one will last at least another 160k.

 

[armentaaw]

Had the same type of leak you described on my 8.1 sub. Dealer replaced the pan seal @ 195000 miles last August. Have had no oil leaks since.

 

[azmike]

I have an oil leak in Yukon with 277,000 miles. I'm not sure if it's coming from the rear main seal or the rear part of the oil pan gasket or if there is a gasket at the oil filter adapter. The rear main seal was changed with a NAPA brand at about 245,000 miles when I put in a reman transmission. I cannot pinpoint where the leak is coming from even after power washing it clean. I'm losing about just over a quart of oil every 3000 miles. The oil seems to be dripping right where the oil filter is even above it, I just change the oil today too. The whole oil filter is usually soaked as well as the bottom bell housing of the transmission . Last oil change prior I swapped out the oil cooler block off plate gasket with no effect. Has anybody had any issues like this? I'm tired of the large oil spot on my driveway, but I don't mind the rust proofing underneath the truck, LOL.

My 2000 Yukon (5.3) has about 205,000 miles on it. It's still a great vehicle but has been leaking oil for at least 100,000 miles. According to my honest mechanic, it's the real main seal which is common with Yukons. He felt it was better just to put a pan under it and add oil as necessary as opposed to spending a few thousand dollars on a problem that may reoccur again. Funny thing as the vehicle has gotten older the leak as slowed down a little. I'm just going to keep driving it until it literally falls apart.

 

[22YukonDenali22]

I had a shop tell me my similar leak was rear main gasket (seal was dry, per my looking through bell housing hole). I then had some tranny work done, and the tranny shop looked right at the rear main seal and gasket...dry as a bone. So I kept on following the leak up and up the block, to the valve cover. It seemed like oil was sleeping from the valve cover, and air was pushing it to the back of the block. I replaced both valve cover gaskets... No leak since! Obviously, there are tons of potential leak sources...add valve cover gaskets to the potential list!!

 

[Rocket Man]

I had a shop tell me my similar leak was rear main gasket (seal was dry, per my looking through bell housing hole). I then had some tranny work done, and the tranny shop looked right at the rear main seal and gasket...dry as a bone. So I kept on following the leak up and up the block, to the valve cover. It seemed like oil was sleeping from the valve cover, and air was pushing it to the back of the block. I replaced both valve cover gaskets... No leak since! Obviously, there are tons of potential leak sources...add valve cover gaskets to the potential list!!

I hope you replaced the rear main anyway as a maintenance item while the trans was out. It sure would suck if it started leaking a few months or even a year or two later. I did when I had my trans was out, as well as the rear cover and gasket. It had 150k and was the perfect opportunity.

 

[22YukonDenali22]

I hope you replaced the rear main anyway as a maintenance item while the trans was out. It sure would suck if it started leaking a few months or even a year or two later. I did when I had my trans was out, as well as the rear cover and gasket. It had 150k and was the perfect opportunity.

I opted not. At 85k miles in my 2008 Yukon Denali, I let the sleeping dog sleep. I've heard of leaks developing after bad rear main seal replacements. If I can get to 150k miles until rear main seal replacement needs, I'll feel justified. If it starts leaking tomorrow, I'll be bummed! Haha.

 

[Rocket Man]

I opted not. At 85k miles in my 2008 Yukon Denali, I let the sleeping dog sleep. I've heard of leaks developing after bad rear main seal replacements. If I can get to 150k miles until rear main seal replacement needs, I'll feel justified. If it starts leaking tomorrow, I'll be bummed! Haha.

Can’t be afraid of doing maintenance just because some people don’t do it right and have issues. There’s a centering tool that comes with the ACDelco rear main seal that ensures it gets installed right, if you follow directions you’re good to go. I guess if you buy a crappy main seal like a Dorman you deserve what you get. But I’ll never be afraid to replace any and all wear items with OEM quality when they’re buried like that. I mean, your trans went out at that mileage so who’s to say the main seal isn’t far behind. That’s my thinking anyway.

 

[helimd]

I have an oil leak in Yukon with 277,000 miles. I'm not sure if it's coming from the rear main seal or the rear part of the oil pan gasket or if there is a gasket at the oil filter adapter. The rear main seal was changed with a NAPA brand at about 245,000 miles when I put in a reman transmission. I cannot pinpoint where the leak is coming from even after power washing it clean. I'm losing about just over a quart of oil every 3000 miles. The oil seems to be dripping right where the oil filter is even above it, I just change the oil today too. The whole oil filter is usually soaked as well as the bottom bell housing of the transmission . Last oil change prior I swapped out the oil cooler block off plate gasket with no effect. Has anybody had any issues like this? I'm tired of the large oil spot on my driveway, but I don't mind the rust proofing underneath the truck, LOL.

 

[helimd]

You might want to pull the top engine covers off and take a look at the valve cover gaskets. I found a leak that was originating from the right rear valve cover but the oil, at rest, finally dripped on the ground from the front left. Drove me nuts. Replaced the gaskets with Felpro and haven't seen a leak in over a year. Almost the same mileage, by the way. Good luck

 

[Larryjb]

Can’t be afraid of doing maintenance just because some people don’t do it right and have issues. There’s a centering tool that comes with the ACDelco rear main seal that ensures it gets installed right, if you follow directions you’re good to go. I guess if you buy a crappy main seal like a Dorman you deserve what you get. But I’ll never be afraid to replace any and all wear items with OEM quality when they’re buried like that. I mean, your trans went out at that mileage so who’s to say the main seal isn’t far behind. That’s my thinking anyway.

When I saw the condition of the rear cover gasket, I'm surprised that not more of them are leaking. The gasket material became flattened over time and heat cycles so that it was no longer making a seal. I had more leaking from the cover than the rear main itself.

Also, Mark is right that you can't be afraid to replace the seal (done properly). There appears to be some debate about whether to lubricate the crankshaft side of the RMS or not. Teflon impregnated seals are not supposed to be lubricated in any way, shape, or form. The Teflon transfers from the seal to the metal of the crankshaft. Felpro claims that if you lubricate it, it can leak within miles. I have also heard it said that Felpro admitted that lubricating the crankshaft side of the seal doesn't cause it to fail, you just don't get the benefits of the Teflon. The main reasons for failing is improper installation of the seal itself. I gather it is extremely easy to get the lip of the seal pushed aside during installation causing instant leaks.

The other cause of leaks is when guys torque down the pan-to-rear-cover bolts first. This pulls the rear cover down off center from the rear main seal. The rear cover bolts should be tightened first to keep the rear main centered when you torque the rear pan bolts.

Anyway, what's done is done. Hopefully your rear seals will last a long time.