# '08 Siverado 1500 Oil Consumption



## crab.claw (Jun 13, 2008)

Hey All,

I have a '08 Silverado 1500 with the AFM (Active Fuel Management). My truck is around the 65K miles and over the last three oil changes, the oil dip stick has been bone dry. The tech. at the oil changes place has said there is no evidence of any leaks. 

Have any of you guys heard of this? Any experiences? Thoughts?


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## C.Hern5972 (Jul 17, 2009)

Mine has 60k on it and just started doing it as well. I had the oil changed 3k miles ago, it is due and just got a ADD ENGINE OIL light 2 days ago. I cant see any visible leaks. Curious as well....


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## redexpress (Apr 5, 2010)

Which engine is it? 5.3? What kind of oil y'all been using?


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## C.Hern5972 (Jul 17, 2009)

5.3 pennzoil


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## Dawg (Oct 4, 2010)

check the pcv valve,make sure it is not sucking oil,does it smoke on start up in the morning,if if does,could be bad valve stem seals,only thing left is the rings


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## crab.claw (Jun 13, 2008)

5.3
Been using Mobile Synthetic
No sight of any smoke.

Thanks for the advice!


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## Slim-N-None (Sep 16, 2005)

my 07 5.3 z71 was doing it. it was drinking a quart every 1000 miles. it has a bulletin out on it. they had to replace all the pistons and rings. You can not view the bulletins online but the dealership knows about the issue, and has access to them. If i remember right, it was called piston slap. Strickland Chevrolet in Pearland is the dealership that fixed us up.

Here's a link to my thread-
http://2coolfishing.com/ttmbforum/showthread.php?t=315013


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## BIG PAPPA (Apr 1, 2008)

*DON'T ASSUME PISTONS/RINGS*

There are a few bulletins on this. VERY Rarely is it the pistons causing this. It's an 08 and at your mileage, it's under Powertrain warranty. Take it in and let the Pro's handle it..and again, I'll bet it is not the Pistons/Rings.


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## BIG PAPPA (Apr 1, 2008)

*here ya go*

xTooltipElement

2008 Chevrolet Silverado - 4WD | Sierra, Silverado VIN C/K Service Manual | Document ID: 2596962 
#10-06-01-008B: Engine Oil Consumption on Aluminum Block Engines with Active Fuel Management (AFM) (Install AFM Oil Deflector and Clean Carbon from Cylinder) - (Mar 7, 2011)

*Subject:**Engine Oil Consumption on Aluminum Block Engines with Active Fuel Management (AFM) (Install AFM Oil Deflector and Clean Carbon from Cylinder)*

*Models:**2007-2009 Cadillac Escalade, Escalade ESV, Escalade EXT*
*2007-2009 Chevrolet Avalanche, Silverado 1500, Suburban, Tahoe*
*2007-2009 GMC Sierra 1500, Sierra Denali, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL *
*2008-2009 Pontiac G8 GT *
*Equipped with Aluminum Block V8 Engine with Active Fuel Management (AFM) (RPOs LC9, LH6, L76, LFA, L92)*
*with Greater than 45,000 km (28,000 mi)*​
*This bulletin is being revised to add the 2009 model year and new Correction information for the 2009 model year - left rocker arm cover replacement. Information has also been added after step 9. Please discard Corporate Bulletin Number 10-06-01-008A (Section 06 - Engine/Propulsion System). *
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=2596962&from=sm#ss1-2596962">*Condition*​
Some customers may comment about engine oil consumption of vehicles with higher mileage (approximately 48,000 to 64,000 km (30,000 to 40,000 mi). Verify that the induction system is assembled correctly and that there is no evidence that the engine has been ingesting dirty air due to a mis-assembled induction system. Also verify that the PCV system is functioning properly. If diagnostic procedures indicate that oil consumption is piston/piston ring related, verify that oil consumption is less than 3,000 km (2,000 mi) per liter/quart. If these conditions are met and oil consumption is less than 3,000 km (2,000 mi) per liter/quart, perform the service indicated in this bulletin.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=2596962&from=sm#ss2-2596962">*Cause*​
This condition may be caused by oil spray that is discharged from the AFM pressure relief valve within the crankcase. Under most driving conditions and drive cycles, the discharged oil does not cause a problem. Under certain drive cycles (extended high engine speed operation), in combination with parts at the high end of their tolerance specification, the oil spray quantity may be more than usual, resulting in excessive deposit formation in the piston ring grooves, causing increased oil consumption.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=2596962&from=sm#ss3-2596962">*Correction*​
*2009 Vehicles Only*​
*Important: *This left rocker arm cover is NOT to be used on 2007-2008 vehicles because of the calibration of the PCV orifice being different in 2007-2008. 
A new left rocker arm cover has been released for 2009 engines. Technicians should replace the left rocker arm cover with GM P/N 12642655. This rocker arm cover has relocated PCV drain holes that prevents PCV pullover into the intake manifold. Refer to SI for Valve Rocker Arm Cover Replacement - Left Side.
*2008-2007 Vehicles Only*​
To correct this condition, perform the piston cleaning procedure as described in this document, and install a shield over the AFM pressure relief valve per the procedure outlined in this document. Monitor oil consumption after this repair to ensure oil consumption has improved to acceptable levels. If this repair does not correct the condition, it may be necessary to replace the piston assemblies (piston and rings) with new parts.​
*Important: *It is critical in this cleaning process that the engine/fuel injector cleaner remain in the cylinders for a minimum of 2.5 hours to fully clean the components. The cleaner solution must be removed before a maximum of three hours. 
Verify the oil consumption concern following Corporate Bulletin Number 01-06-01-011F. If oil consumption is found, continue on with this bulletin.
Remove the spark plugs and ensure that none of the pistons are at top dead center (TDC).
Clean the pistons by putting 118-147 ml (4-5 oz) of Upper Engine and Fuel Injector Cleaner, GM P/N 88861802 (in Canada, use 88861804), in each cylinder. Allow the material to soak for at least 2.5-3.0 hours, but no more than three hours and then remove the cleaner. A suggested method of removing the cleaner is cranking engine over. Make sure to unplug the ignition coils and fuel injector before cranking the engine over. Also make sure that the painted surfaces are covered so no damage is done.
Remove the oil pan. Refer to Oil Pan Replacement in SI.











[*]Remove the AFM valve (1). 









[*]Install the new shield (1), GM P/N 12639759, and tighten the AFM valve to the oil pan to 28 N​


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## crab.claw (Jun 13, 2008)

Wow! Thanks Big Pappa. 

Now I wonder what I should do. Start tracking the millage with the dealer or start looking for a new one. Kind of at a decent spot in my lon time line to where if i could get the right deal then maybe... Geeze! I was hoping to drive this one into the ground...


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## Slim-N-None (Sep 16, 2005)

BIG PAPPA said:


> There are a few bulletins on this. VERY Rarely is it the pistons causing this. It's an 08 and at your mileage, it's under Powertrain warranty. Take it in and let the Pro's handle it..and again, I'll bet it is not the Pistons/Rings.


It probably isn't, but all they have to do is a quick compression test to see if it is a piston/ring issue. If you have the gauge you could check it and save yourself having to drop it at the dealership for a day. And I agree, let the pros handle it since its under warranty, ours hasn't taken a drop since they fixed it.


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