Help Diagnosing Oil leak

lspann3525 · Friday at 1:39 AM

Well im back again with another oil leak after a couple of oil pan gasket changes,rear mail seal replacement and valve cover gasket replacement.

Lately ive noticed my 08 tahoe has been drinking oil so I decided to check the oil pan area and I discovered the front area of the oil pan is covered in oil. I doubt its the oil pan gasket. I replaced it maybe 10 months. Im trying to pin point this im thinking maybe timing cover seal or crankshaft seal??? Anything else in this area that can cause this mess. Heres a video.. any suggestions will help.

donjetman · Friday at 8:56 AM

lspann3525 said:
Well im back again with another oil leak after a couple of oil pan gasket changes,rear mail seal replacement and valve cover gasket replacement.

Lately ive noticed my 08 tahoe has been drinking oil so I decided to check the oil pan area and I discovered the front area of the oil pan is covered in oil. I doubt its the oil pan gasket. I replaced it maybe 10 months. Im trying to pin point this im thinking maybe timing cover seal or crankshaft seal??? Anything else in this area that can cause this mess. Heres a video.. any suggestions will help.

Oil consumption:
Install a catch can and have you or a PO installed the improved driver side valve cover per GM TSB# 10-06-01-008M? https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

When you had the pan off, I hope you installed a new oil pump to pickup tube o-ring? Also, a dab of rtv is needed where the parting line of the front & rear covers meet the oil pan gasket.

Last summer I changed the timing cover gasket, pulley, seal, o-ring, VLOM, etc, etc, etc:
https://www.tahoeyukonforum.com/threads/valley-cover-crank-pulley-etc.149036/

lspann3525 · Friday at 10:08 AM

I havnt installed the updated valve cover yet. I installed new gm pick up tube o-ring and put 4 dabs of rtv where the block meets the covers.

I want to assure its the timing cover gasket sort of hard for me to tell where its coming from. I cleaned that area up during the last oil change so where the leak is coming from its getting worser.

What made you change your timing cover gasket?

donjetman · Friday at 11:24 AM

lspann3525 said:
I havnt installed the updated valve cover yet.

In 2018 at 130k miles when we bought our road hard and hungup wet Yukon, the piston rings were stuck from sucking & burning oil because of the the poor original valve cover pcv design. Poor pcv performance/vacuum can cause crankcase gaskets to leak due to too much positive crankcase pressure. Today it has 199k miles and does NOT use any oil.

lspann3525 said:
I installed new gm pick up tube o-ring and put 4 dabs of rtv where the block meets the covers.

thats good

lspann3525 said:
What made you change your timing cover gasket?

It had a small oil leak from ?somewhere? on the front of the engine.
The 2 piece pulley balancer is held together with rubber and we all know rubber doesn't last forever so I changed it and the seal.

donjetman · Friday at 12:51 PM

In 2018, when I had the oil pan off, I also installed the afm valve deflector shield GM# 12639759 ($8) per the TSB instructions, even though my engine is NOT afm equipped.

lspann3525 · Friday at 8:14 PM

Is there an updated aftermarket driver side valve cover?? I was quoted 146 locally..

rdezs · Friday at 8:28 PM

Here's a link to a set I bought on Amazon for my Hummer H2:

Updated valve covers

Quality was awesome, unbelievable for the price. And they look really good.

lspann3525 · Friday at 9:04 PM

Thanks! Thats a pretty good deal. I will consider this for my gen 3 rebuild. Im going to try to find the cheapest driver side valve cover thats updated to see if that slows down the oil consumption. My oil pan /timing cover seems to be leaking. So ill start with the valve cover

Are all the valve covers with the part number 12570427 updated??

Ebay and Amazon are full of 12570427 aftermarkets that are half the price

Left Driver Side 12570427 Valve Cover For 1999-2008 Cadillac Chevy GMC Pontiac | eBay

Replaces part number: 12570427. 2006-2007 Cadillac CTS V8 6.0L Left Valve Cover. 2004-2005 Cadillac CTS V8 5.7L Left Valve Cover. 2002-2008 Cadillac Escalade Left Valve Cover. 2007-2008 Chevy Avalanche V8 6.0L Left Valve Cover.

www.ebay.com

https://www.amazon.com/JDMSPEED-Replacement-Cadillac-1999-2008-12570427/dp/B09B3N465V/ref=sr_1_1?crid=36DSA0D5DKQ1H&dib=eyJ2IjoiMSJ9.ZJAllszU-vSHHKWAzPoV-6y8__axjp3kYjaCAuqSCEn-S8ysh6k9UVkBXJpE8rhCm1jCmsdKzGTK9buS2ybZZP155C3aUtvVAONozpq0S8csX52tuBqDRT-nYvEQF1XlUzbesOWx3sexNrbfsW6WFQSc6t_tZQJFbcbILexwA1wSfvu0Ew4azWZOTyqgL31aPT2nhrolSzmmjB1Hv0uwCQXHDQISTlG3zHOw6GgEs7kIhEiGrwPIL5p0wB74T_K3a6kL9uKSHpYWSceIapqasjBYoOnYSkQWj6wPmaWKjq93ko8qZ5hQ8w23iT1ZoxK4x2wu-OQTv4XMSfD8bknqc8sabrIjSchqxgUAjPvntAc.zKZeHBLMs0uy85iz2ned4eEvHXxcFgM1yzthcw3g3L0&dib_tag=se&keywords=12570427&qid=1734746235&s=automotive&sprefix=12570427+%2Cautomotive%2C199&sr=1-1

lspann3525 · Friday at 9:10 PM

They all seem to have the rectangle opening instead of the round opening as well.

rdezs · Friday at 10:20 PM

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

Help Diagnosing Oil leak

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Left Driver Side 12570427 Valve Cover For 1999-2008 Cadillac Chevy GMC Pontiac | eBay

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