Help Diagnosing Oil leak

[donjetman]

Judging from your old valve cover, you have a lot of engine blow by either past the rings or valve seals. Or simply a plugged PCV hose. Should look sort of golden inside. Below picture is an LS 6.0 at 120,000 miles, oil changes every 4,000 miles.

View attachment 445948

Had another set of heads on the shelf ready to go, and since I was pulling these off to change minor head gasket leak.... Put the other set of heads on with updated valve covers
View attachment 445949
View attachment 445950

That's a gen 3, not the issue us gen4 owners have.
gm shafted us 2007 to 2011 gen4 owners by selling us vehicles with a defective pcv system, see this TSB: https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

 

[donjetman]

View attachment 445940

Received the new valve cover and gasket yesterday. I went ahead and changed the oil last night and installed the new valve cover.

Time to put some miles on the truck I'll report back.

WOW. Thats worse lookin than mine was .
I added a catch can first and was catching 1 oz of oil every 100 miles. After the ds vc change and combustion chamber/piston soak it dropped to next to nothing, and remains that way still.
Be very careful if you use any product(s)/oil(s) to clean it up. If something breaks free it may plug-up an oil passage, the dog bone, a bypass, etc, etc.
HPL sells a 30w oil specially designed to desolve the crud. Multiple frequent oil filter changes are a must.
https://www.advlubrication.com/products/engine-cleaner

 

[rdezs]

It's possible the rings are just gummed up. That solvent stuff you had to the oil makes me nervous though. I've seen some LS oil pumps suddenly lose pressure.... And found little tiny pieces of grit in the pressure relief valve. It would also make me nervous if any little pieces made their way to a lifter. The filter should catch it, but then again on a cold start with high oil pressure, some oil bypasses the filter through the oil filter pressure relief valve above the oil filter on some, and built into the oil filter on others. I can't remember what you said your mileage was. If it's around 200,000 miles, it's probably a little bit of everything. (Rings, valve guides and valve seals)

 

[rdezs]

Yes, that picture of the inside of my head is a generation 3..... With a lousy PCV system that I upgraded to the newer 6.2 style valve cover. The old one actually used a PCV valve.... Looks like it had been doing its job properly though.

 

[j91z28d1]

Yes, that picture of the inside of my head is a generation 3..... With a lousy PCV system that I upgraded to the newer 6.2 style valve cover. The old one actually used a PCV valve.... Looks like it had been doing its job properly though.

I believe the pvc valve was a good design for years. even the only ls sports cars didn't start drinking tons of oil till they did away with it. even moving to the lifter valley from the valve cover didn't fix it completely.

catch can the world haha

 

[j91z28d1]

It's possible the rings are just gummed up. That solvent stuff you had to the oil makes me nervous though. I've seen some LS oil pumps suddenly lose pressure.... And found little tiny pieces of grit in the pressure relief valve. It would also make me nervous if any little pieces made their way to a lifter. The filter should catch it, but then again on a cold start with high oil pressure, some oil bypasses the filter through the oil filter pressure relief valve above the oil filter on some, and built into the oil filter on others. I can't remember what you said your mileage was. If it's around 200,000 miles, it's probably a little bit of everything. (Rings, valve guides and valve seals)

I think the way he did it by soaking the rings shouldn't increase the risk of running gunk thru the oil pump as much as the oil stuff.

 

[rdezs]

That's definitely preferable to the stuff you add to your motor oil.

 

[lspann3525]

It's possible the rings are just gummed up. That solvent stuff you had to the oil makes me nervous though. I've seen some LS oil pumps suddenly lose pressure.... And found little tiny pieces of grit in the pressure relief valve. It would also make me nervous if any little pieces made their way to a lifter. The filter should catch it, but then again on a cold start with high oil pressure, some oil bypasses the filter through the oil filter pressure relief valve above the oil filter on some, and built into the oil filter on others. I can't remember what you said your mileage was. If it's around 200,000 miles, it's probably a little bit of everything. (Rings, valve guides and valve seals)

Yep im at 275xxx.

 

[lspann3525]

Do yall think marvel mystery oil would help any??

Next time I change plugs i'll try the piston cleaning procedure

 

[mikez71]

I thought MMO was what they used back in the day for stuff like this? (I never did so no experience here)

 

[rdezs]

275,000 mi? LOL, it's had a good life.... And it's a good candidate to try those different cleaning chemicals. Just be prepared though.... It's quite possible carbon buildup is what's keeping the compression

 

[donjetman]

It's possible the rings are just gummed up. That solvent stuff you had to the oil makes me nervous though. I've seen some LS oil pumps suddenly lose pressure.... And found little tiny pieces of grit in the pressure relief valve. It would also make me nervous if any little pieces made their way to a lifter. The filter should catch it, but then again on a cold start with high oil pressure, some oil bypasses the filter through the oil filter pressure relief valve above the oil filter on some, and built into the oil filter on others. I can't remember what you said your mileage was. If it's around 200,000 miles, it's probably a little bit of everything. (Rings, valve guides and valve seals)

Its not solvent stuff, its Valvoline Premium Blue "RESTORE" engine oil, developed by Valvoline for Cummins for a piston ring sticking problem they have.
I did a lot of reseach.

 

[rdezs]

Sounds better than the one quart of engine flush I think they still sell.

 

[lspann3525]

Spent some more time under the truck today and noticed the passenger side rack and pinion boot is wet this could be what's causing the front cover to be oily

 

[donjetman]

Spent some more time under the truck today and noticed the passenger side rack and pinion boot is wet this could be what's causing the front cover to be oily

I feel your pain, mine's doing it on the drivers side

 

[lspann3525]

Did you use the proper tool to center the timing cover when you had it off for the seal? Sort of necessary for the front and rear main seal on LS engines....

Front and Rear Cover Billet Alignment Tool

https://a.co/d/6BYWsUm

Quick Question I went with the Dorman Rear Cover that had the seal already installed and I didnt use the alignment tool I just made sure the rear crankshaft seal was good all the way around . The instructions called for me to use a dorman alignment tool but looking at how the dorman tool works its no different than just placing the cover on the crank and gently pushing the cover. The dorman tool just sits on the rear face of the crankshaft. But I just learned that some guys install the cover without the seal and use the alignment tool to align it. Im considering redoing mine and installing new cover gasket and seal pressing it in after its been aligned with the tool.

Anyone else out there use the dorman rear cover without alignment tool??? I just dont see how the dorman tool can align the cover when the tool doesnt go around the crankshaft

 

[rdezs]

The proper alignment tool slides rather snugly around the end of the crankshaft, and also fits rather snugly in the seal bore in the housing. So yeah, with the proper alignment tool you install the rear cover without the seal installed. Then when you're done, you can use the same alignment tool to gently tap the rear seal in. Note that from the factory the rear seal is almost flush with the outside edge of the rear cover. It's okay and often advisable on higher mileage engines, to go ahead and tap the seal that extra 3/16 of an inch in. It will bottom out against the flange, and the seal will ride on a section of the crank that is like new, never had a seal rubbing on it.

 

[donjetman]

Anyone else out there use the dorman rear cover without alignment tool???

I did NOT use any alignment tool when I did the rear main seal/cover (2018) and front cover/seal (last summer). No leak

 

[rdezs]

I did NOT use any alignment tool when I did the rear main seal/cover (2018) and front cover/seal (last summer). No leak

Hopefully it lasts.... I had to redo a rear main seal, about 8,200 mi after the previous owner did it without the tool. Didn't leak much, but I always found a droplet then some dampness..... Below picture is what I found

The seal itself is spring loaded, it will seal a while if not actually centered properly.... But it definitely won't last as long as it should.

 

[donjetman]

Hopefully it lasts....

My Dorman rear main seal cover w/seal = 6+ yrs & 69k miles so far

r m s job: https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

frt cover job: https://www.tahoeyukonforum.com/threads/valley-cover-crank-pulley-etc.149036/ I'll keep my fingers crossed