For the 3.9 L engines (RPO codes LZ8 (vin "R") and LZG (vin "3")) in the 2007 and 2008 Impalas the AFM lifters are no longer being manufactured so as a result GM has released a TSB #13-06-01-002 on 6/26/2013 detailing on how to convert the engine to a non-AFM engine. All it requires is a conversion kit part# 19299225 that contains the parts necessary to do the conversion and a special code to get the new ECM calibration that is also required. The parts in the kit include a new camshaft, lifters, lifter guides, and a LOMA oil block off plate.
3.9L Active Fuel Management Decativation
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Good info, such a shame though, the 07-08 LTZs get very good mileage on the highway when running with AFM on.
In my casual daydreaming, I'd had thoughts of putting an AFM equipped 3900 from the wreckers into a lighter Malibu Maxx SS for a more fuel efficient daily driver.
In my casual daydreaming, I'd had thoughts of putting an AFM equipped 3900 from the wreckers into a lighter Malibu Maxx SS for a more fuel efficient daily driver.
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I saw a very solid 1.2L/100km difference on the highway with my Dodge Hemi with their identical version of cylinder deactivation. 1.2L/100km = 3 MPG in US gallons. The system does work, 100%, and not in a totally insignificant way.
By its nature, the current setup will consume oil but everyone's interpretation of how much oil consumption is "an issue" is different. Some people say they have blue smoke puff out the back when the system disengages, that's an issue. Others are probably annoyed that they have to actually their their dipstick levels every month, actually do maintenance, those people I don't sympathize with and its hard to know who just makes a fuss.
I will say, if I could have my 6.2 LS3 in my Trailblazer run in DoD mode on the highway and gain me 3MPG, I would. I guess I'm the minority who like the cylinder deactivation system.
By its nature, the current setup will consume oil but everyone's interpretation of how much oil consumption is "an issue" is different. Some people say they have blue smoke puff out the back when the system disengages, that's an issue. Others are probably annoyed that they have to actually their their dipstick levels every month, actually do maintenance, those people I don't sympathize with and its hard to know who just makes a fuss.
I will say, if I could have my 6.2 LS3 in my Trailblazer run in DoD mode on the highway and gain me 3MPG, I would. I guess I'm the minority who like the cylinder deactivation system.
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Bart...that's COOL!!
Do you have a link to a readable version, or the dealer printouts!??!
I'll have to get my dealer to print it for me!
As I've babbled here previously, my '08 LTZ 3.9L AFM burns oil at a decent rate. This past winter, I did an oil-consumption test with my dealer. It burned 1.5 Qts. in 3,400 miles. I ran Mobil-1 thru the whole time.
From a "Geek" standpoint, I like the AFM system! Mine switches in-&-out seamlessly. Since spring, I've been using the GM "Full-Dino" oil...no diff. noticed in oil-burning unfortunately...:dunno::bang:....
I don't really care bout gas-mileage, but it WOULD be nice to NOT burn oil!!!!
Faron
Do you have a link to a readable version, or the dealer printouts!??!
I'll have to get my dealer to print it for me!
As I've babbled here previously, my '08 LTZ 3.9L AFM burns oil at a decent rate. This past winter, I did an oil-consumption test with my dealer. It burned 1.5 Qts. in 3,400 miles. I ran Mobil-1 thru the whole time.
From a "Geek" standpoint, I like the AFM system! Mine switches in-&-out seamlessly. Since spring, I've been using the GM "Full-Dino" oil...no diff. noticed in oil-burning unfortunately...:dunno::bang:....
I don't really care bout gas-mileage, but it WOULD be nice to NOT burn oil!!!!
Faron
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158 Posts
No problems here with the AFM, yet.
Oil consumption is in the 2,500 miles per quart range - not too concerned about it, given the miles accumulated. When the vehicle was newer (< 50,000 miles), was figuring in the 6-7,000 mile per quart range.
Given the parts listed for the conversion, figure I can buy a whole lot of oil
On the other hand, should something in the engine fail requiring this conversion, due to lack of available original replacement parts - now that would scorch my shorts.
Oil consumption is in the 2,500 miles per quart range - not too concerned about it, given the miles accumulated. When the vehicle was newer (< 50,000 miles), was figuring in the 6-7,000 mile per quart range.
Given the parts listed for the conversion, figure I can buy a whole lot of oil
On the other hand, should something in the engine fail requiring this conversion, due to lack of available original replacement parts - now that would scorch my shorts.
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412 Posts
Cylinder deactivation is going to use some oil in its operation. When cylinder deactivation begins, the exhaust valve opens on the final exhale and then the intake valve never opens, neither does the exhaust valve again until that cylinder is reactivated.
In that dead cylinder, as the piston pumps up and down, a vacuum is created, strong enough to draw some oil from the crankcase past the piston rings and into the combustion chamber, which is then burnt off when the cylinder reactivates.
If the consumption is excessive, more than a quart per 2500 miles, I'd try some fuel injector cleaner in several tankfulls of gas in succession, and also add some GM EOS (Engine Oil Suppliment) which will help clean the bottom oil control piston rings. Fuel injector cleaner twice per year is not a bad idea either way.
In that dead cylinder, as the piston pumps up and down, a vacuum is created, strong enough to draw some oil from the crankcase past the piston rings and into the combustion chamber, which is then burnt off when the cylinder reactivates.
If the consumption is excessive, more than a quart per 2500 miles, I'd try some fuel injector cleaner in several tankfulls of gas in succession, and also add some GM EOS (Engine Oil Suppliment) which will help clean the bottom oil control piston rings. Fuel injector cleaner twice per year is not a bad idea either way.
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The main cause of the oil-use is the oil-spray on the bottom of the "dead" cylinders, which of course did build up some between the rings, leading to increased oil-burning.
One of the fixes for all the AFM-V8's, besides the top-engine cleaner soak-time regimen, was a new oil-pan gasket with a metal oil-deflector tab that reduced/eliminated oil-spray. This tsb is linked in the forum here somewhere! I've had them printed at my dealer too.
There was never a part/pan designed for AFM 6's like mine though...
Proportionately, my 3.9 burns MORE oil than the V-8's!!!:gaah:
That's why I'm so interested in Bart77's notice of the NEW TSB!!!
Faron
One of the fixes for all the AFM-V8's, besides the top-engine cleaner soak-time regimen, was a new oil-pan gasket with a metal oil-deflector tab that reduced/eliminated oil-spray. This tsb is linked in the forum here somewhere! I've had them printed at my dealer too.
There was never a part/pan designed for AFM 6's like mine though...
Proportionately, my 3.9 burns MORE oil than the V-8's!!!:gaah:
That's why I'm so interested in Bart77's notice of the NEW TSB!!!
Faron
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9 Posts
I have been curious about also. I have a 08 LTZ with the 3.9L AFM engine. I have no problems with it being noticeable when changing from 3 to 6 cylinders, there is no smoke out of the tailpipe, but it does use oil, not a lot, but like mentioned before, the oil level goes down faster than an 8 cylinder. The crankcase only holds 4 quarts, so it needs monitored. I didn't realize a camshaft change was necessary for a conversion. I have changed cams, but it might be necessary to pull the engine on an Impala? There is a company that has a module that will plug into the 0BD 2 receptacle to shut off the AFM, its $200, and I wonder if it would help that much with the oil using problem? They have some pretty good mechanics at my dealership, I wonder if they ever get a call to do these conversions and what the $$$ would be. I bet it is not cheap. I only have 50K on mine. I think I will keep a few quarts of oil in the trunk, so I always have some oil handy. Thanks for the info.
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20 Posts
Arm deactivate
I have decided to switch trans into 3rd gear below50 mph then switch to 4th above that,this will keep car in 6cyl mode,and poss keep oil consumption to a min,I watch cyl mode on my dash.will watch oil level.
I have decided to switch trans into 3rd gear below50 mph then switch to 4th above that,this will keep car in 6cyl mode,and poss keep oil consumption to a min,I watch cyl mode on my dash.will watch oil level.
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Bass master, staying in 3rd gear as you suggest is a good idea, thanks, I will try it. I found another use for using 3rd gear, when cruising on the highway and then taking another road like our entrance to our airport, I slowed down, then I noticed the car wants to keep rolling at its previous speed, while I was looking for my quickly approaching turn off, so 3rd gear makes it easier to control the speed also.
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3rd gear
Yep thinking staying in 6cyl mode a little longer will keep my plugs from fouling cause I was two qts low on oil,way too much oil consumption for 80,000 mi.with religious oil changes from day one.gm can kiss my oily grits.
Yep thinking staying in 6cyl mode a little longer will keep my plugs from fouling cause I was two qts low on oil,way too much oil consumption for 80,000 mi.with religious oil changes from day one.gm can kiss my oily grits.
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On the 3.9 engines it will cycle from 6cyl to 3cyl mode as needed,I can be doing 40mph and it could be in 3 cyl mode if I'm not accelerating hard,it manages fuel consumption but now it appears it could be a cause for high oil consumption also.
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