The infamous oil leak

[NC_John]

I've been screwing around chasing the infamous engine oil leak on my 02 and after doing the oil pan gasket, intake manifold set (was hoping it was one of the sensors on the rear top of the intake) and as a hail mary- the valve covers, I finally bit the bullet yesterday and did the rear main.



A buddy let me use a lift at his shop and I got it done yesterday. He said it was a four hour job which I don't believe, even for a "professional mechanic." Took me 12. A lot of time was wasted trying to find tools (as I was working at his place, not mine so I couldn't find anything). He didn't give me a lot of help, mostly laughed at my phoentic cursing and then went home and took a nap. The main was definitely wet and I changed both the rear cover gasket and the main seal (the kit was less than $25 at Napa). I also serviced the tranny (dumped the fluid, changed the filter, removed and replaced the tail extension o-ring.

The worst part of the job, believe it or not, was trying the get the tranny dipstick tube back in place (f*cked with it for probably an hour), and trying the figure out the damn circlips on the tranny cooler lines (I dropped one, it disappeared on the shop floor and I spent 40 mins looking for it).

I had a 20 mile drive back to the house. No leaks yet.... Tranny felt good. My fluid was definitely worn/brown but the pan and the filter element looked good (looked original too) after 200K miles.

Fingers are crossed that the SOB leak is finally fixed....

 

[JonnyTahoe]

I'm sure if you were to do the job again you could do it in Half the time. Just be thankful you had access to a lift that would of been a nightmare on your back and i'm sure someone out there has done it too. Thanks for the info my girlfriend has a 2000 and I suspect the seal but there is also oil on the oil pan bolts so I can relate to your frustration after doing a pan gasket and still no fix. I Wont do a Main myself and I give you lots of credit for even attempting it. I hate leaks too, I bet your's was leaking like her's where you have lots of drips and the bottom of the bell housing is all wet and the exhaust has oil from blowing back as you drive. Thanks so much for writing this thread it was just the info I needed to figure out what I'm going to do and Not Do. J T.

---------- Post added at 03:26 PM ---------- Previous post was at 03:03 PM ----------

As you can see John those Seals are only good for about 10 years, and 200,000 mi. I guess that is pretty good if you figure how many hours of operating time that is. I feel your pain, I did a water pump once and about a month later had a coolent leak that was hard to see where it was coming from so I did the intake and all along it was the water pump gasket that I know I did right so I used two gaskets the second time and it took care the leak. Thanks for including the picture it shows everything you need to remove.

 

[NC_John]

I'm sure if you were to do the job again you could do it in Half the time. Just be thankful you had access to a lift that would of been a nightmare on your back and i'm sure someone out there has done it too. Thanks for the info my girlfriend has a 2000 and I suspect the seal but there is also oil on the oil pan bolts so I can relate to your frustration after doing a pan gasket and still no fix. I Wont do a Main myself and I give you lots of credit for even attempting it. I hate leaks too, I bet your's was leaking like her's where you have lots of drips and the bottom of the bell housing is all wet and the exhaust has oil from blowing back as you drive. Thanks so much for writing this thread it was just the info I needed to figure out what I'm going to do and Not Do. J T.

---------- Post added at 03:26 PM ---------- Previous post was at 03:03 PM ----------

As you can see John those Seals are only good for about 10 years, and 200,000 mi. I guess that is pretty good if you figure how many hours of operating time that is. I feel your pain, I did a water pump once and about a month later had a coolent leak that was hard to see where it was coming from so I did the intake and all along it was the water pump gasket that I know I did right so I used two gaskets the second time and it took care the leak. Thanks for including the picture it shows everything you need to remove.

I could do it quicker now I'm sure- I took a lot of care during disassembly and reassembly- everything got cleaned before it went back on and I put everything back EXACTLY like it came off. No broken clips or harnesses, nothing bent. Just like it was supposed to be. A production shop would have just hauled ass to get it done in book time and not care what they screwed up in the process.

I've got over 1,000 miles on the repair now (drove the truck to northern MI) and it is bone dry underneath so I can say with confidence the leak is no more. Too bad my freaking windshield washer froze and I've not been able to clean my windshield in days. Damn its cold up here! Going back south tomorrow! It should thaw out around Detroit I'm guessing....

 

[KAKALAK]

 

[A623Z]

Yeah it was the rear main for mine too, squeaky clean driveway ever since

 

[afpj]

NC john,
Thanks for that pic. It explains alot. Had mine replaced few months back, but still got a leak and can't seem to find it. My question for you (or anyone) is about housing alignment. At the bottom of the tranny bell housing, where it mates to the oil pan (where that little half circle cutout is near the larger view hole), is the flat bottom perfectly flush with that of the oil pan, right where it mates? I could swear mine was perfectly flush/level before, but after the most recent repair the tranny bell housing sits about 1-2 mm below the level of the oil pan shelf at that mating surface. Looking and feeling through the view hole, I no longer have oil around the flywheel, so that's better, but still have oil collecting right where the bell housing and oil pan meet. I guess I'm going to work backwards and look at the valve covers next. Thanks for any info you could give, and I hopoe I made sense.

 

[NC_John]

NC john,
Thanks for that pic. It explains alot. Had mine replaced few months back, but still got a leak and can't seem to find it. My question for you (or anyone) is about housing alignment. At the bottom of the tranny bell housing, where it mates to the oil pan (where that little half circle cutout is near the larger view hole), is the flat bottom perfectly flush with that of the oil pan, right where it mates? I could swear mine was perfectly flush/level before, but after the most recent repair the tranny bell housing sits about 1-2 mm below the level of the oil pan shelf at that mating surface. Looking and feeling through the view hole, I no longer have oil around the flywheel, so that's better, but still have oil collecting right where the bell housing and oil pan meet. I guess I'm going to work backwards and look at the valve covers next. Thanks for any info you could give, and I hopoe I made sense.

Everything lined up on mine the way it came off. I didn't notice anything out of alignment when I put it back together. Did you check that little blank/block-off plate just above the oil filter mount? I've been told those are prone to leakage as well.

 

[afpj]

Everything lined up on mine the way it came off. I didn't notice anything out of alignment when I put it back together. Did you check that little blank/block-off plate just above the oil filter mount? I've been told those are prone to leakage as well.

Hey thanks, yes that blank/block has been addressed. The leak there was making it look like my filter was the culprit for part of it. As far as alignment goes, yeah I cannot 100% remember if that bottom tranny housing is perfectly smooth with the oil pan at that mating area. I thought it was a "perfect" alignment with no step from bell housing to oil pan at that bottom horizontal surface, but now I am doubting myself. Didn't know if yours has a small step there or was smooth and flat like I "though" I remembered. Suks to get old.

 

[AZ-Yukon]

NC john,
Thanks for that pic. It explains alot. Had mine replaced few months back, but still got a leak and can't seem to find it. My question for you (or anyone) is about housing alignment. At the bottom of the tranny bell housing, where it mates to the oil pan (where that little half circle cutout is near the larger view hole), is the flat bottom perfectly flush with that of the oil pan, right where it mates? I could swear mine was perfectly flush/level before, but after the most recent repair the tranny bell housing sits about 1-2 mm below the level of the oil pan shelf at that mating surface. Looking and feeling through the view hole, I no longer have oil around the flywheel, so that's better, but still have oil collecting right where the bell housing and oil pan meet. I guess I'm going to work backwards and look at the valve covers next. Thanks for any info you could give, and I hopoe I made sense.

I had oil leaking down the back side of the engine, dripping out just in front of the bell housing. It turned out to be a leaky oil pressure sensor. It is located behind the intake manifold. These things fail quite often. Mine stopped reporting pressure properly some time before it started leaking. Just a thought for something else to check.

 

[DenaliAK]

Just spent a bus-load of money, 4 trips to the mechanic, and about a week total of the truck being down tracking down all my leaks. They'd fix one and find another. It was ridiculous. Basically, after almost 170k miles, just about everything that could leak, did leak.

Holding my breath we got it all. I could've almost completely replaced the engine for the amount I'm into the parts and shop time.