Is Your Gmt-900 Truck Or Suv Using Oil

[studly]

This oil consumption problem started on my 2008 4WD Suburban a few months ago at about 70,000 miles. It used 2 quarts in the last 2000 miles.

 

I'm getting the fixes installed next week. They include installing a new valve cover and AFM shield.

[Cowpie]

Hope the fixes cure the problem. This whole oil consumption thing about these engines is ridiculous. Kinda makes one wonder what the back room boys in R&D were smoking when they came up with this AFM stuff.

Edited December 14, 2013 by Cowpie

[dataspng]

Well it just got serious... Took it in for oil change today and it only had 3 quarts left in the pan with DIC still reading 40% oil life... so looks like consumption just went up. Time to talk to Chevy and start the process.

[studly]

The original PCV design allowed for too much oil to pass out of valve cover and back into intake manifold. Oil would then pool in cavities of intake and spill over into cylinders when you stop at red light on incline, park on slope, etc.

 

Interesting. That would explain the modified valve cover. Why is there also a need for an AFM oil deflector in the oil pan?

[studly]

Bought and installed the Range V8 module last spring. Oil usage appeared to completely stop for a couple of months. Since then, over a few long trips in hot weather, my truck is using oil again. Maybe not as much as before the Range, but is still using some. D*mn!!! Looks like I'll have to have a dealer tear into the engine, which I was trying to avoid if at all possible.

Does your vehicle have the valve cover/AFM shield modifications yet?

[studly]

Just got my 2008 Suburban back today with the valve cover/AFM shield modifications. I will definitely be keeping an eye on the oil consumption.

 

Is the general concensus that it is a good idea to get the Range V8 module anyway?

I'd rather lose a little fuel economy if it will prolong the life of the engine.

[MaverickZ71]

Does your vehicle have the valve cover/AFM shield modifications yet?

 

No, not yet. Probably will have my dealer do it next spring, before the powertrain warranty expires. Hopefully those TSB modifications, in conjunction with the Range V8 module, will finally end the oil usage problem. I just wish the General would've come clean about the AFM problems earlier and done a recall instead of a TSB just because they want to keep it on the down-low. There's gotta be a few million GM trucks/cars/SUVs out there with this problem, but no doubt the General does not want to derail its comeback program.

Edited December 20, 2013 by Maverick Z71

[hillbilly4u]

Thought I would drop back in for a spell. I see there are more guys trickling in on the oil usage thread.The fix is rings, pistons and valve cover. I had to pay for new plugs. Although the dealer done a good job on mine, it still gave me unease to know my engine had been broken down.

[HateCarpetGuy]

Time for me to re-visit: my 08 CC 4wd 5.3 w/ high mileage: I used to burn oil 2-3 qts/5K mi. Had a compression test done first to see if rings were bad, all good psi. Rolled the dice and had AFM turned OFF via computer reprogram at local speed shop, new PCV valve cover upgrade installed, new plugs installed just to start clean. After > 100K since improvements. there has been ZERO oil loss between changes, NONE. The old race car engine builder that reprogrammed computer said "these 5.3's are great engines once you get the 'bleeping' govt out of the motor". His words were aimed at the mechanically illogical AFM system, the theoretical striving for inc fuel ratings to pacify the EPA, and on and on and on.

 

My mileage as of Dec. 20: 315K and still runs strong and I drive it everyday and would hesitate to road trip to wherever. Guys, you have to change to latest valve cover/PCV design to stop oil from free flowing onto top of intake to slurp over into engine, and my engine has seen no loss in fuel mileage (either hand calc or computer) by turning OFF AFM and running 8-cyl all the time. Like my dog prefers to walk on 4 legs instead of 2 or 3.

Stand with Phil.

[studly]

I still don't understand the mechanism of this failure.

How does AFM make it suck oil? What is different when AFM is engaged?

And how do the rings go bad?

One post said the problem is that oil gets sucked through the PCV valve into the manifold. How does that make the rings go bad?

 

Also, I can understand the valve cover change to help prevent oil from going into the PCV valve. What does the AFM shield in the oil pan do?

[Cowpie]

And this confirms my reasoning behind my disabling the AFM the minute I brought my 2013 home from the showroom. I brought my military mind and my business mind to the table regarding this. I believe in a team effort. Since I bought 8 cylinders, they all were required to work 100% of the time.

 

This union mindset of letting some of the cylinders take smoke breaks and what not while the others had to work was not going to fly in my vehicle. Everyone has to do their part. No one gets to ride in the wagon while the others pull. I voided this union like agreement the first day my vehicle got onto my property. I realize that the government has held sway over much of the operation of GM for a while, but I was not about to allow my engine to be like a government group, whereby half the people stand around and watch the other half work. No sir. Wasn't going to happen on my watch. Except for maybe a few miles on the vehicle when it still belonged to the dealer and was test driven, the AFM has been non-functional.

 

Just like the above post where his dog prefers to walk on all fours, a working environment where everyone is packing the gear makes for a harmonious environment where everyone gets along. Such is the case for my engine. No cylinders slacking of here! No oil usage, no problems. Since last oil change, 5829 miles on the oil. Oil level is at the first notch below full. That is about half a pint or 8 oz. The oil catch can on the PCV line has captured about 4 oz of oil so that leaves 4 oz the engine is using elsewhere. I can live with that.

Edited December 20, 2013 by Cowpie

[Screwderado]

I have a extend cab 2008 Silverado . 5.3L no flex . 2wd. LT. The only mods I have is a driveshaft disconnect because the vehicle is used as a TOAD. A while back I took my truck to the local stealership and performed a oil burn test. Before I took it in I checked the oil and it was in fact a quart low after the 1,000 mile drive. I took it back and they informed me that the missing quart had miraculously appeared in my crankcase ! When I asked for proof low and behold there it was . I must of been a bad boy since because I recently changed the oil and after 1.300 miles my crankcase was 3 quarts low. If you have one of these oil burner GM's face it your SCREWD!!!!!!!!!!!!!!!!!

[Screwderado]

I also forgot to mention this was right before my powertrain warrantee expired . The oil sucker in question has about 95K on it now.

[MaverickZ71]

Time for me to re-visit: my 08 CC 4wd 5.3 w/ high mileage: I used to burn oil 2-3 qts/5K mi. Had a compression test done first to see if rings were bad, all good psi. Rolled the dice and had AFM turned OFF via computer reprogram at local speed shop, new PCV valve cover upgrade installed, new plugs installed just to start clean. After > 100K since improvements. there has been ZERO oil loss between changes, NONE. The old race car engine builder that reprogrammed computer said "these 5.3's are great engines once you get the 'bleeping' govt out of the motor". His words were aimed at the mechanically illogical AFM system, the theoretical striving for inc fuel ratings to pacify the EPA, and on and on and on.

 

My mileage as of Dec. 20: 315K and still runs strong and I drive it everyday and would hesitate to road trip to wherever. Guys, you have to change to latest valve cover/PCV design to stop oil from free flowing onto top of intake to slurp over into engine, and my engine has seen no loss in fuel mileage (either hand calc or computer) by turning OFF AFM and running 8-cyl all the time. Like my dog prefers to walk on 4 legs instead of 2 or 3.

Stand with Phil.

 

 

HCGuy, did you also get the "AFM shield" installed in the oil pan, or just replace the valve cover with the one with the "AFM baffle" in it?

[dsmmace]

Anybody check plugs to see if a certain cylinder had more ash deposits on it than the rest?