CodyC6

I haven't been under either of mine lately to see, but some of you commented on finding slight leaks during oil changes etc. Sorry if this is old news, just saw it posted on the Trailblazer SS site regarding the LS2 and other LS engines.

Subject: 5.3L LC9, LS4, L33, LH6, LM4, 5.7L LS1, LS6, 6.0L LS2, L76, 6.2L L92, 7.0L LS7 - Engine Oil Leak at Rear Cover Assembly Area (Engine Block Porosity RTV Repair Procedure) #05-06-01-034E - (02/12/2007)


Models: 2004-2007 Buick Rainier

2005-2007 Cadillac CTS-V

2007 Cadillac Escalade, Escalade ESV, Escalade EXT

2003-2007 Chevrolet Corvette, TrailBlazer

2004-2006 Chevrolet SSR

2005-2007 Chevrolet Silverado, Silverado SS

2006-2007 Chevrolet Impala SS, Monte Carlo SS, TrailBlazer SS

2007 Chevrolet Avalanche, Suburban, Tahoe

2003-2007 GMC Envoy, Sierra

2004-2005 GMC Envoy XUV

2007 GMC Yukon XL, Yukon Denali, Yukon XL Denali

2004-2006 Pontiac GTO

2005-2007 Pontiac Grand Prix GXP

2005-2007 Saab 9-7X

with 5.3L, 5.7L, 6.0L, 6.2L, 7.0L VORTEC™ GEN III or GEN IV V8 Engine (RPOs LC9, LS4, L33, LH6, LM4, LS1, LS6, LS2, L76, L92, LS7)

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This bulletin is being revised to update warranty information. Please discard Corporate Bulletin Number 05-06-01-034D (Section 06 -- Engine/Propulsion System).


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Condition
Some customers may comment on an engine oil leak.

Cause
Upon initial diagnosis, it may be determined that the leak is coming from the rear cover gasket. This condition may be caused by engine block porosity on the sealing surface. This issue pertains to aluminum block applications only.

Correction
Follow the steps for Oil Leak Diagnosis in SI to determine the source of the leak. If the leak has been diagnosed as coming from the engine rear cover assembly, refer to Engine Rear Cover Replacement in SI and remove the engine rear cover assembly. Inspect for engine block porosity where the engine rear cover mates to the engine block. If porosity is found anywhere on the sealing surface, use the following procedure to apply RTV to repair the engine block porosity. Refer to the illustration below.


Important: Clean any residual oil from the block and cover before applying the sealant in the next step.

Wipe a small amount of RTV, P/N 12378521 (in Canada, use P/N 88901148), onto the surface using a plastic scraper to fill the porosity.
Remove any excess RTV material, especially from inside the high pressure oil passage. Refer to #1 in the above illustration.
The joint may be closed immediately after applying the RTV. Total joint time after the RTV has been applied must be under 20 minutes.
Important: Refer to Engine Rear Cover Replacement in SI and follow the tightening specifications and sequence.

Reinstall the engine rear cover using a new gasket and a new crankshaft rear main seal. Refer to Engine Rear Cover Replacement in SI.
Parts Information
Important: For Saab (U.S.) only, use P/N 12345795, Engine Oil Dye (U.S.), or equivalent.

Part Number
Description
Qty

12574293
Gasket - Crankshaft Rear Oil Seal Housing
1

89060436
Seal, Crankshaft Rear Main
1

12378521 (U.S.)

88901148 (Canada)
Sealant
1

12345795 (U.S.)
Dye, Engine Oil
1

10953470 (Canada)
Dye, Engine Oil
1


Warranty Information
Excluding Saab U.S. Models
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

J7510*
Oil Leak -- Rear Cover Area -- Porosity Repair

CTS-V
5.5 hrs

Corvette

- M/T

- A/T


5.9 hrs

5.4 hrs

SSR
5.4 hrs

TrailBlazer/Envoy/Rainier/Saab 9-7X (Canada)

- 2WD

- 4WD


5.7 hrs

6.5 hrs

GTO

- M/T

- A/T


10.2 hrs

10.5 hrs

Grand Prix/Impala/Monte Carlo
5.7 hrs

Silverado//Sierra Models

- M/T

- A/T


4.5 hrs

5.5 hrs

Avalanche, Escalade, Suburban, Tahoe, Yukon Models
4.5 hrs

Add
With skid plate
0.2 hr

With HP2**
0.5 hr

To clean parts over 48,000 km (30,000 mi)
0.1-0.3 hr

* This labor operation is for bulletin use only. It will not be published in the Labor Time Guide.

** HP2 Hybrid Propulsion Electric, AHS2


Saab U.S. Models
For vehicles repaired under warranty, use:

Labor Operation
Description
Failed Object
Fault/Reason Code
Location Code
Warranty Type
Repair/Action Code
Labor Time

2161901
Replace part, Seal, End Plate V8 T-Truck
21619
57
0
01
01
6.5 hrs

Add

9821001
R&R Anti-Submarine (Skid) Plate
--
--
--
--
--
0.2 hr

Add
To clean parts over 48,000 km (30,000 mi)
--
--
--
--
--
0.1 to 0.3 hr in 99 time




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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© Copyright General Motors Corporation. All Rights Reserved.

fugereb

I have a minor rear main leak going on, confirmed at the dealer. Not overly excited about getting this fixed.

juice3

Just woke up to a major rear main leak under warranty. - Grrrr. I'll direct them to this TSB.

Eritosthenes

This is not good news. Reading between the lines, this appears to be something that the foundry has been aware of for quite a while, and that they made a major change to their block casting procedures starting with the 2008 model year. Porosity is not the kind of flaw that develops or evolves. It's either there or it isn't. I wonder how reliable (and repeatable) the application of RTV sealant would be on a porous surface under a gasket. Given its location, it's quite possible such a casting flaw and its attendant leak might not be pinpointed until after the 100,000 mile drive train warranty has expired. Then what?