Bad news for GM!

[greatgab]

Do you have excessive oil consumption?
https://www.autoweek.com/news/indus... been found,surrounding the Vortec LC9 engine

 

[BainMan]

Did the Avalanche ever get the LC9? This Wiki claims yes for 2007-2013, however I'm almost certain my 2010 has LMG motor (iron block instead of aluminum). I certainly burn oil between changes. Updating the drivers valve cover reduced the consumption, but it is still present.

 

[greatgab]

The LC9 started in 2007 - fixes were done in late 2010 and early 2011 to reduce oil misting and blow by in the PCV system. Turns out that the piston rings were junk! GM knew about the rings but didn't want to spend the money to fix them, one of their TSBs said that burning 1 quart per 2K miles was normal! If the oil level drops, then the oil pressure drops, which drives the AFM/DOD system crazy.

 

[ToyHauler13]

I've got the LC9 (aluminum/flex fuel) engine. I thought the iron block was what was put in the 2X4 trucks and the 4X4 models got the LC9.
110K and doesn't burn a drop and it better stay that way!!

 

[BainMan]

8th VIN digit on my 2010 4x4 is 0, which is LMG if the online lookup tools are correct. Is your 8th digit a '3' for LC9?

 

[ToyHauler13]

My 8th digit is a 7
This is what I got in a VIN search for the Build Sheet and all the related RPO code descriptions: Engine: (LC9) ENGINE FLEXIBLE FUEL, (GAS/ALC), 8 CYL, 5.3L, SFI, ALUM, CYL DEACT, GM

 

[ygmn]

glovebox sticker will let you know all the rpo codes for your truck.

 

[BainMan]

My 8th digit is a 7
This is what I got in a VIN search for the Build Sheet and all the related RPO code descriptions: Engine: (LC9) ENGINE FLEXIBLE FUEL, (GAS/ALC), 8 CYL, 5.3L, SFI, ALUM, CYL DEACT, GM

Oh I see in 2013, 7 is the LC9... Is your truck 4x2 or 4x4?

I'm still curious on which 2nd gen trucks got the iron block vs aluminum!

 

[Wpolonavyguy]

Did the Avalanche ever get the LC9? This Wiki claims yes for 2007-2013, however I'm almost certain my 2010 has LMG motor (iron block instead of aluminum). I certainly burn oil between changes. Updating the drivers valve cover reduced the consumption, but it is still present.

Try the catch cans, only trouble is need rigid tubing for high vacuum. I first used rubber fuel lines they collapse & make idle rough & lots other computer dumb adjusting. I used copper rigid lines both sides.
Passenger side can almost never gets much oil as I'd guess location on intake less suction strength. My driver's side I still get about a half cup oil every few months even with modified valve cover with different pickup location.

 

[EXT4ME]

Passenger side is the filtered air inlet at the throttle body to the crankcase.

Probably not much oil at that location.

Maybe a little, but I would not suspect much.

Driver's side is crankcase air headed toward the top of the intake and it dumps downstream from the port for the clean air.

My catch can is plumbed into the driver's side tube and it caught a lot of nasty stuff back when I found out I have a cracked driver's side head that was seeping coolant down into the crankcase.

The catch can provided the best clue to that problem.

 

[ToyHauler13]

Oh I see in 2013, 7 is the LC9... Is your truck 4x2 or 4x4?

I'm still curious on which 2nd gen trucks got the iron block vs aluminum!

Mine is a 4x4.
Looking at the Chevrolet Press release for the 2009 Avalanche it states:

At the beginning of the 2009 model year, Avalanche comes with a 5.3L aluminum-block V-8 as standard on 4WD models, delivering 310 horsepower (231 kW)* and 335 lb.-ft. (454 Nm)* of torque. Shortly after start-up production, the standard engine will change to a 5.3L iron-block V-8 with 320 horsepower (239 kW) and 340 lb.-ft. of torque (461 Nm), with Active Fuel Management and FlexFuel capability.

There is no mention of the type of 5.3L Vortec used for years 2010 & 2011. I'm assuming the iron block.
Then the release for 2012 & 2013 states:

• Vortec 5.3L with an iron cylinder block is used on 2WD models (engine code LMG).
• Vortec 5.3L with an aluminum cylinder block is used on 4WD models (engine code LC9).

This is what I was able to find from Chevy.