GM DOD/AFM Interesting Oil Observations

[TiredTrucker]

Well, I wasn't about to play wait and see with any possible AFM issues. I disabled the AFM on my 5.3L at 245 miles on the odometer. Could it have done just fine leaving it stock? Possibly, but I wasn't going to play that round of poker. I could care less if it is less than 1/2 of 1%, or whatever, of the AFM engines that have a problem. I didn't want to play in that sand box. I didn't ask for AFM, I wasn't given the option of not having it, but I don't want it, so it went bye-bye.

It is one thing to risk problems when you are doing a mod on your own, with your own money. It is quite another when the OEM forces it down your throat. Kinda like the Daytime Running Lights. They are not mandated, but GM is bound and determined you are going to get them whether you like them or not. Doesn't matter that it can spook cattle when you go and start your pickup while repairing fence out in the pasture. And sometimes it is better to drive around livestock in a stealthy kind of way. So the DRL fuses got pulled and the DRL function went bye-bye also. Just still haven't gotten around to disabling the low light sensor that turns on headlights. Another pearl from the minds of the R&D department at GM. At least I have gotten into a well established habit of quickly flipping the light switch to disable it when I start the pickup.

Cut out all of this goofy stuff that GM did, and it is a pretty decent pickup.

 

[Durango]

tony1679,

In my 08' Impala SS with only 33K on it so far I've noticed no oil consumption to make a big deal yet. I use Mobil 1 5W-30 and it runs just fine. Just took a quick trip to Palm Springs and the AFM did fantastic! It'll be ready for another service soon so my GM dealership will keep an eye on the engine for me. Perhaps you need to start using Mobil 1 as well. It's kept me happy for years.

Durango

 

[Nobody]

Originally Posted By: wag123
Not only are GM's and Chrysler's cylinder deactivation systems plagued with known problems (indicated and admitted-to by all of the manufacturer TSBs that have been issued), but Honda is also having problems with theirs, and some people believe that Honda is THE advanced engine technology leader/expert. So, that makes it a clean sweep, ALL of the manufacturers that use this technology are admittedly having problems with it.
Personally, I don't like the way that any of these engines react/respond in real-world driving conditions, and I wouldn't hesitate for one second disabling this "feature" if I owned a vehicle that had it.


Honda even tested their cylinder deactivation in the Japanese domestic market before exporting it to the US. In Japan, because of the registration/inspection system it become progressively more expensive to own a car as it ages, so few people keep a car past something like 4-5 years. So the Japanese car companies know they can test long term reliability of new technology in the domestic market without burdening owners with a piece of junk for long if it doesn't work out. Plus Japanese car owners are more willing to overlook a bad car from a brand and consider another car from that brand.

 

[SteveSRT8]

Originally Posted By: jrustles
To Steve and all others with no issues with AFM, how much time do your vehicles spend in the mode?? Sporadically or a lot? How much steady cruising do you guys do?

The only time we used it a LOT was on a trip home. We normally ship our vehicles from the Factory Authorized Upfitter in MA to FL but the expense is now nearly 2 grand so we flew up and drove it back. Approximately 1300 miles, we averaged 16 mpg at an average speed of 70 mph!

Extended van, 6.0 gasser weighing about 8800 pounds with the two of us in it. Vans like this simply do not get that kind of mileage at 85 mph, much less when brand spanking new!

I learned how far I could push it while staying in AFM mode, the limit was 85-87 mph for me. The vehicle did not use a DROP of oil, and now with over 30k miles on it it still has never moved visibly on the dipstick. But our urban route definitely won't use AFM much, especially considering this vehicle leaves the lot at 9200-9400 pounds every single day.

The simple fact is that despite the folks declaring dramatically that "the TSB's show the defect exists" NO ONE HERE has any idea how many are involved. And to the folks who declare that "they all drive funny" the GM system as implemented in our fleet is virtually imperceptible by most any driver. You can only feel it by the dramatic change in the throttle programming, the shift in and out of 4 cylinders is simply not noticeable by most drivers...

 

[threeputtpar]

Originally Posted By: Kuato

Originally Posted By: threeputtpar
I agree that AFM implemented in the GM 3.9l (and the 5.3l) in the Impala is not their best work. My SIL has an 08 and if she stays in town it uses very little oil. When she drives home to visit the family, it uses 1.5 quarts in each 150 mile direction.

That is totally unacceptable. If it wasn't for her family having money from directly working for GM in the past, there's no way she would have bought that car.


Holy moly threeputtpar, 1.5 quarts in a 150 mile trip? I'd be disconnecting that system asap.



Yep, she knows to check and fill the oil before she leaves her apartment and when she gets here has me check it again and top off. It's usually 1 - 1.5 quarts, and then I give her the 1/2 quart and another full one for the drive home. Pretty insane for a sump that only takes 4 quarts to begin with.

She'll be trading it in sometime in the next year, so she just lives with it for now. It also has the oh-so-reliable 4T65 trans that cost her a grand last year when it just stopped shifting out of 1st gear. She thought it was hilarious that where it stranded her she had to drive a mile or two to safety, with the engine screaming at nearly the redline to get out of traffic.

 

[A_Harman]

Originally Posted By: lexus114
Originally Posted By: jrustles
Originally Posted By: tony1679
Originally Posted By: MolaKule
Me too.

We have a 2008 TrailBlazer with the 5.3L V8 and I have used every oil in the industry, including mine (since it is one of my test mules), and have had zilch oil consumption since new.


So are you saying your 5.3 has AFM but is not having issues? Congrats if that is the case. But if you think I'm wrong, you're mistaken. The only variable that changed was the AFM being disabled. Same oil, same filter, same everything.


Glad the tuner worked out for you! I'd disable AFM at the first opportunity too, TBH

There's just something dumb about continuing to pay inertial and friction costs by dragging the rotating/reciprocating assy around as dead weight to save fuel lol. It just seems like such a backwards way to increase efficiency. Sure, one could work three (or four) cylinders closer to their lowest BSFC, and hope that offsets pumping, inertial and friction losses, but it doesn't strike me as a smart thing to do. It also wears half the engine out more than the other half. At 200K miles, what will we have, one bank with more ring wear than the other? larger bearing clearances on one bank vs the other? more piston pin bore wear?

What about the dragging cylinders, did the engineers really think that the same gas pressure would remain sealed in the closed, dead cylinder?? Ya right, more like it'll stabilize at mid stroke, drawing a vaccuum below half stroke and positive pressure above half stroke. Then there is the oil on the cylinder walls not getting scraped off properly due to no gas pressure on the rings, which could foul up the cylinder with oil. Then there are the unpleasant harmonics...
It's just a weird concept to me, for such an idea to make it to market.


Agree with this post 100%


Well that's nice. But jrustles is mistaken in his reasoning.

 

[A_Harman]

So far in this thread, I count more people who don't have oil consumption problems with their AFM than people who do. If GM was having excessive problems with the AFM system, they would have pulled it off the market by now. Instead, they have expanded use of AFM to include the LT1 in the Corvette, the 5.3 and 6.2 Gen V V8's in the pickups, and the new 4.3 V6 in the pickup. The 4.3 deactivates two cylinders, leading to odd firing intervals. (bang-bang-skip-bang-bang-skip)

Cylinder deactivation is here to stay, and its use will expand in the future. Europeans are talking about putting deactivation on I4 and I3 engines.

 

[TiredTrucker]

It may be here to stay from a OEM point of view, but it will get deactivated from many owners point of view. Just like daytime running lights are here to stay from some OEM's. Likewise, those of us that don't want them will just deactivate them. I have deactivated the daytime running lights on 5 of my vehicles so far and counting. Deactivated the AFM on one, so that is the start of things to come if they keep shoving it my direction.

 

[A_Harman]

That's your prerogative as owner of the car. But you wouldn't be buying the car at all if it wasn't available because it couldn't meet CAFE standards. And don't get me wrong; I think the CAFE law is an abomination to its roots.

 

[splinter]

Negligible consumption through ~5% OLM OCIs with our AFM LMG 5.3 and its DRLs have yet to spook cattle.

 

[tony1679]

Originally Posted By: Durango
tony1679,

In my 08' Impala SS with only 33K on it so far I've noticed no oil consumption to make a big deal yet. I use Mobil 1 5W-30 and it runs just fine. Just took a quick trip to Palm Springs and the AFM did fantastic! It'll be ready for another service soon so my GM dealership will keep an eye on the engine for me. Perhaps you need to start using Mobil 1 as well. It's kept me happy for years.

Durango


Again, I get BETTER mileage without AFM and now I have ZERO consumption. WHY WOULD I CHANGE A PERFECT RESULT?

P.S. - Give it time, you'll eventually have an oilholic and hate it too.

 

[tony1679]

This thread has been somewhat blown out of proportion, I simply presented observed facts.

I have no idea if GM has improved the technology over the years. The 2011+ years may be just fine. But here is what I do know, the 2006-2009 models are NOT fine. I'm sure there are some in that range of years that are ok. But a lot are not. The tsb confirms this. Saying I'm wrong and then comparing a model 3-5 years newer to prove it is idiotic. So is comparing at 33k mile car to a 100k mile car.

Also regarding afm, what most do not know is that there are other side effects GM has cleverly covered up. When mine was using oil, I noticed a frequent rotten egg smell. Oil was being burned off in the catalytic converter. Before I learned of the afm issue, I addressed this with two different dealers. Instead of acknowledging their afm flaw, they both called me crazy and sent me away with paperwork stating that it was caused by not using top-tier fuel. Which I already was using. And before anyone asks "how do you know your cat was related to afm? What if it was already going bad?" The cat was replaced two months before I bought the car. Put 2 and 2 together... afm oil killed the first one.

Bottom line - everyone is entitled to their own opinion. Mine has been stated. But opinions are irrelevant. I presented facts. These are my "test results." And I am completely satisfied with them.

 

[Mike_dup1]

Here is a little snippet from an explanation on how AFM works. Oil consumption was anticipated it would seem.

Quote:
By deactivating the exhaust valve first, this allows the capture of a burnt air/fuel charge or exhaust gas charge in the combustion chamber. The capture of exhaust gases in the combustion chamber will contribute to a reduction in oil consumption, noise and vibration levels, and exhaust emissions when operating in V4 mode.


A very good friend is a GMC salesman and he had told me AFM oil burning is a problem for a lot of the early 07-11 engines. He has/had an 07 Sierra 5.3 CC 4wd that started using a lot of oil at 30,000+ miles. He had one of the pistons on his desk from his engine and the rings were welded to the piston.

Note - TSB
#11-06-01-007: Engine Oil Consumption with Active Fuel Management (AFM) (Install Oil Pan Gasket and Clean Carbon from Cylinder) - (Nov 22, 2011)

 

[Mike_dup1]

time for editing ran out

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.

 

[tony1679]

Originally Posted By: Mike_dup1
Here is a little snippet from an explanation on how AFM works. Oil consumption was anticipated it would seem.

Quote:
By deactivating the exhaust valve first, this allows the capture of a burnt air/fuel charge or exhaust gas charge in the combustion chamber. The capture of exhaust gases in the combustion chamber will contribute to a reduction in oil consumption, noise and vibration levels, and exhaust emissions when operating in V4 mode.


A very good friend is a GMC salesman and he had told me AFM oil burning is a problem for a lot of the early 07-11 engines. He has/had an 07 Sierra 5.3 CC 4wd that started using a lot of oil at 30,000+ miles. He had one of the pistons on his desk from his engine and the rings were welded to the piston.


Ding ding ding! Somebody gets it...

Out of curiosity, does your Sierra have afm?

 

[A_Harman]

Originally Posted By: tony1679
Originally Posted By: Mike_dup1
Here is a little snippet from an explanation on how AFM works. Oil consumption was anticipated it would seem.

Quote:
By deactivating the exhaust valve first, this allows the capture of a burnt air/fuel charge or exhaust gas charge in the combustion chamber. The capture of exhaust gases in the combustion chamber will contribute to a reduction in oil consumption, noise and vibration levels, and exhaust emissions when operating in V4 mode.


A very good friend is a GMC salesman and he had told me AFM oil burning is a problem for a lot of the early 07-11 engines. He has/had an 07 Sierra 5.3 CC 4wd that started using a lot of oil at 30,000+ miles. He had one of the pistons on his desk from his engine and the rings were welded to the piston.


Ding ding ding! Somebody gets it...

Out of curiosity, does your Sierra have afm?


But did you read Mike's continuing post? The problem only affects engines that are driven at continuous high speeds and that were built at the high end of the tolerance band. So now that you know the facts, are you willing to back off of your position that AFM is evil?

 

[Mike_dup1]

Quote:
Out of curiosity, does your Sierra have afm?

No, I have the 6.2L engine and in 2012 it did not have AFM. I did not want an AFM engine, had 1 of them and never like the way it vibrated at slow speeds so I got rid of it and bought a 6.2L that did not have it. I only put 24,000 miles on the AFM and had a chance to sell it and buy the Denali and took it.

Note - The TSB snippet I mentioned is just one of many dealing with the AFM engine and oil consumption.

Quote:
If this repair does not correct the condition, it may be necessary to replace the piston assemblies (piston and rings) with new parts.
Correction
A new oil pan gasket has been released. Technicians should replace the oil pan gasket. This oil pan gasket has the AFM shield incorporated into the gasket. Refer to SI for Oil Pan Gasket Replacement.

 

[tony1679]

Originally Posted By: A_Harman
But did you read Mike's continuing post? The problem only affects engines that are driven at continuous high speeds and that were built at the high end of the tolerance band. So now that you know the facts, are you willing to back off of your position that AFM is evil?


That's funny my commute is 60/40 city/hwy. Mixed. And I'll bet my life savings that salesman didn't drive 100% highway. Less than 7 years old and rings welded to a piston? I'd love to hear an excuse for that. High end of the tolerance band? Sounds like GM should have narrowed it. I'll take my "facts" from first hand experience. Not assume something I read is true about something I don't own.

No matter how people want to nitpick this, GM screwed up. In one manner or another. I corrected their screw up. For my application, afm IS evil. So no, I will not back off. Will the fix I found work for everyone? Maybe. Maybe not.

What's that overly used phrase? Oh yeah.... RESULTS MAY VARY.

 

[MolaKule]

Originally Posted By: BrandonT
I thought the main reason these engines used oil wasn't the cylinder deactivation per se, but the feature (can't remember what) that causes oil vaporization in the oil pan (maybe then making more oil able to make it into the deactivated cylinder)? That said, does anyone know if the 3.6L HFV6 have this oil vaporizing gizmo?


Here is (one of) the TSBs relating to this situation:

Quote:
#11-06-01-007: Engine Oil Consumption with Active Fuel Management (AFM) (Install Oil Pan Gasket and Clean Carbon from Cylinder) - (Nov 22, 2011)
Subject: Engine Oil Consumption with Active Fuel Management (AFM) (Install Oil Pan Gasket and Clean Carbon from Cylinder)

Models: 2008-2009 Buick LaCrosse/Allure
2006-2007 Chevrolet Monte Carlo
2006-2009 Chevrolet Impala SS
2005-2008 Pontiac Grand Prix GXP
Equipped with V8 Engine RPO LS4

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 greater than 0.946 L (1 qt) in 3,200 km (2000 mi). If these conditions are met and oil consumption is greater than 0.946 L (1 qt) in 3,200 km (2000 mi), perform the service indicated in this bulletin.
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.

To correct this condition, perform the piston cleaning procedure as described in this document, and install the new oil pan gasket 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.
Correction
A new oil pan gasket has been released. Technicians should replace the oil pan gasket with GM P/N 12643081. This oil pan gasket has the AFM shield incorporated into the gasket. Refer to SI for Oil Pan Gasket Replacement.

To correct this condition, perform the piston cleaning procedure as described in this document, and install the new oil pan gasket 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 all of the piston assemblies (piston and rings) with new parts. Refer to SI for repair procedure.
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.

1. Verify the oil consumption concern following Corporate Bulletin Number 01-06-01-011G. If oil consumption is found, continue on with this bulletin.
2. Remove the spark plugs and ensure that none of the pistons are at top dead center (TDC).
3. 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.
4. Remove the oil pan. Refer to Oil Pan Replacement in SI.
Important: Ensure that the engine cleaner is thoroughly removed before reinstalling the spark plugs. Failure to do so may result in a hydro-lock condition.
5. Reinstall the spark plugs. Replace the spark plugs if necessary due to full of carbon. Refer to the parts catalog.
6. Reinstall the oil pan. Refer to the Oil Pan Installation procedure in SI. Replace the oil pan gasket.
7. Re-evaluate the oil consumption. Document on the repair order. If the oil consumption is still greater than 0.946 L (1 qt) in 3,200 km (2000 mi), replacement of the pistons and rings will be required.
Important: Some minor scratches may be noticed on the cylinder walls during piston and ring replacement. If the scratch cannot be felt when running your finger nail over it, the scratch is considered normal wear and the block or engine should not be replaced.


Note: It is not necessary to hone or deglaze the cylinder walls. Honing may induce unnecessary cylinder wall and / or piston ring damage if it is done incorrectly and/or not cleaned thoroughly. Cylinder walls should cleaned thoroughly with brake cleaner before installation of the new pistons and rings. Numerous engines replaced for oil consumption have been inspected. The cross hatch has been consistently good and is in specification. As a result, is should not be necessary to measure the cylinders if they pass the visual inspection.

Parts Information

Part Number: 12643081 Oil Pan Gasket
Part Number: 88861802 (in Canada, use 88861804) CLEANER, F/INJR 16 OZ LIQUID POUR (Upper Engine and Fuel Injector Cleaner)

 

[zuluplus30]

Originally Posted By: tony1679
Originally Posted By: A_Harman
But did you read Mike's continuing post? The problem only affects engines that are driven at continuous high speeds and that were built at the high end of the tolerance band. So now that you know the facts, are you willing to back off of your position that AFM is evil?


That's funny my commute is 60/40 city/hwy. Mixed. And I'll bet my life savings that salesman didn't drive 100% highway. Less than 7 years old and rings welded to a piston? I'd love to hear an excuse for that. High end of the tolerance band? Sounds like GM should have narrowed it. I'll take my "facts" from first hand experience. Not assume something I read is true about something I don't own.

No matter how people want to nitpick this, GM screwed up. In one manner or another. I corrected their screw up. For my application, afm IS evil. So no, I will not back off. Will the fix I found work for everyone? Maybe. Maybe not.

What's that overly used phrase? Oh yeah.... RESULTS MAY VARY.


+1. Our 2009 was most definitely not a highway queen. Started consuming at around 35K and sold after the TSB completion with around 59K. Roughly 15k per year driving about 60/40 highway. A couple of 300-500 mile trips annually and lots of boat towing which ironically means it spent lots of time in 8cyl mode.