At my wits' end with oil leaks

[LongbowFoSho]

'02 Tahoe 4WD w/ 240k on the clock. A pretty massive leak. It needs around a quart every two weeks.

So far I've replaced:

- Oil sending unit
- Intake manifold gaskets
- Valley cover gaskets
- Valve cover gaskets

All of those were visibly leaking except for the valve covers, so I was hopeful. I decided to go ahead and replace those while I had everything else out of the way.

Absolutely zero improvement from these repairs. The more I look underneath this thing, the more oil I find and I swear to GOD the leaks are getting worse. The only good news is that the oil pressure remains constant. It was fluctuating between 30 at idle and 80 under a load when I bought it, but now it stays pretty damn steady between 55-60, so at least something seems to have improved.

Anyways, back to my Tahole. I've done a lot of reading on these things and the only culprits left seem to be either the oil pan gasket or the rear main. Based on the pictures below, I'm just going to go ahead and assume that it's both.

Any other leak-causing, engineering abortions that I might have missed?

 

[iamdub]

Judging by the oil inside the bellhousing, I'd say you at least have a rear main leak. Judging by the amount everywhere else, I'd say oil pan gasket. After those, there's nothing else left to leak oil.

 

[Erickk120]

Judging by the oil inside the bellhousing, I'd say you at least have a rear main leak. Judging by the amount everywhere else, I'd say oil pan gasket. After those, there's nothing else left to leak oil.

x2

 

[LongbowFoSho]

I also have a disappearing coolant problem. It tells me low coolant every week. No visible leaks anywhere. I have a verrrrry bad feeling.

 

[WTTAHOE]

I had a similar situation with my 04 Tahoe. I replaced the oil pan gasket and valve cover gaskets chasing a leak. I eventually realized my leak was on the right side of the timing chain cover. The oil was not visible in the cracks and crevices until it ran down/back and leaked around the pan. It has been three months since I replaced the timing chain gasket and no more leaks. Looking back the oil pan gasket needed to be replaced as it was a contributor to the leaks, valve covers were probably OK all along. Good luck because it is frustrating!

Sent from my SM-G955U using Tapatalk

 

[adriver]

I also have a disappearing coolant problem. It tells me low coolant every week. No visible leaks anywhere. I have a verrrrry bad feeling.

It could be something as simple as a radiator cap, and could be as costly as new heads. Search "coolant" or "coolant loss". This thread is about oil. After you search and read up on it, you should post a new thread, or slim chance on bringing up an old one that is more in depth but you need a little more help with.

EDIT: Just realized you started this thread.. I still stand by my comment as the two are not related, other than somebody let maintenance go.

 

[eohat]

I had a similar problem on my ’02 Silverado w/215k miles. The leak was fixed by replacing the oil pan gasket. The old gasket was leaking at the rear, which made it look like it might be the rear main seal. I stuck a telescopic inspection mirror in the bell housing along with a light and was able to rule out the rear seal being bad. You can also use an inexpensive USB inspection camera attached to your phone to look inside the bell housing too.

 

[adriver]

You can get those cameras for less than $10. Helps with a lot of things around the house too.

 

[LongbowFoSho]

I actually have a Harbor Freight snake camera. I'll shove that up there and look while I do the oil pan gasket.

 

[LongbowFoSho]

nm