Active Fuel Management on Chevys

[Sandberm]

  So I bought my dads 08 Chevy Silverado 4x4 1500 with the 5.3 engine this past summer.  It currently has 71,000 miles.

   In doing casual internet research the past few years on the truck I kept reading bad things about the engine. Excessive oil consumption all of a sudden and possibly a cylinder going bad as early as 55,000 miles, but usually between 65 and 125k miles. I did some more research this past week and stumbled upon the why behind the oil consumption. I didn't know it, but the engine has Active Fuel Management(AFM) where it shuts half the cylinders off when not needed. This is apparently what causes the engine to go bad. I had no idea that vehicles that far back were using this technology. I guess there is a range of years that my truck falls into where this problem occurred.

   I then found a device made by Range technology called an AFM disabler that plugs into the OBD2 port that as you probably would guess shuts this feature off so its always in V8 mode. $189. I bought one last week, plugged it in and it defiantly makes a difference. Much better throttle response. What I thought was excessive shifting of the transmission, I now believe was partly due to the engine going back an forth between 4 and 8 cylinders . I hope I got out in front of this problem and I can put many miles on this truck.

My question is, has anybody else had engine problems due to AFM on their Chevy truck? Has anybody else bought this device and if so, how does it work long term? Any other thoughts on the 5.3 engine from this year of Chevy?

[hughjorgan]

I have 12’ with the AFM and considering doing what you just did. It is burning oil, only has 115k miles on it. Never really noticed it burning oil when it was my daily driver.

[BrandonWatts]

Been running a range afm disable on my 14 for the past year and a half. Truck has 75k on it and hasn’t burned any oil yet. Couldn’t stand the 4v mode with exhaust on the truck. Sounded terrible. So far so good.

[Woodchuck]

I have seen several trucks with this issue and you did good to get out front of it. In my experience once the progression starts it's too late to stop it. 

[Bronson]

my '11 was burning oil almost from the get-go.  Since it was "in-spec" which if i remember correctly was burning about a quart between oil changes, nothing to do.  That truck lasted about 4 months past the 5 hear warranty and was having oil pressure issues, this was at 80k miles.  Took it in, and the engine was going bad, no pressure in the lower end.  Traded it in (with full disclosure), bought a Tundra and havent looked back.  I was a dedicated chevy guy until that.  Other than a couple of features like auto 4x4, I am happier with the Tundra, more comfortable, more room.

[Cylvertip]

Yes, had the issue on my wife's 08 Sub with the 5.3. Really ramped up around 140K. Was going through quiet a bit of oil and did not realize why.
   I did some research and ended up buying  a Super Chip tuner to disable the AFM and keep it in V8 mode.  I also ran Sea Foam through it for 500 miles and prior to an oil change and have changed to using Castrol High Mileage  in it exclusively now.  It still burns some oil, but a a far slower rate than before.  I may have to add a quart total in between oil changes now. It was burning two quarts or better a week when we realized it had an issue.  I thought the place that had been changing the oil had not been filling it properly. 
Oil pump failed and it only had a quart in it when the dash lit up like a Christmas tree on 1-5. That was a panicked call from the wife.  I had put 2 + quarts in it the week before.  Thought maybe the plug or filter had fallen off when I had the wife check the oil as I headed her way.  Dealer offered to go in and rebuild the motor for 3K or a new motor for 8K I think.  I had them replace the pump and then did the above.  That was almost 20K miles ago now.  I should probably do the Sea Foam again.

[BrandonWatts]

Some of the oil issues with the 5.3 burn oil is the oil rings on the piston get gunked up with carbon causing oil to go by the rings. The afm just seems to accelerate the problem. I’m hoping to get another trouble free year out of my gmc and then back to diesel for me.

[jackelope]

What the manufacturer calls acceptable and what people think is ok/not ok are 2 totally different numbers. When the 8.1 GM engine came out in the HD trucks back in the early 2000's, GM told us a quart every 1000 miles was normal. All engines use some oil, and the bigger the engine, the more it's going to use was what the technical assistance guys told me back then. Fast forward to now. Ford says a quart of oil every 3k miles is normal in all of the F150 engines.

[brocka]

I have that exact same truck. Same year and everything. I bought it with 14,000 miles on it and I just surpassed 175,000. Yes I add a quart here and there and stay up on oil changes. I was told that if you do the delete kit you void your warranty and since I have a lifetime warranty I do not want to void it.

Anyway, been a great rig. Hope to get another 100k out of her!

[deerlick]

We replace alot of those engines due to afm lifters failing and wiping out the cam and sending metal all throughout the engine. Jasper engines sells a non afm replacement with a module to flash the pcm for the non afm engine and it is a 50 state legal fix.

[BeWitty]

I was burning 1-2 quarts of oil every 4000 miles on my 12’. I fouled a spark plug at 80k miles and started doing some research and discovered the common AFM issue. I bought the Range AFM disabler and don’t burn any oil. Have had the Range for 40k miles and it’s been well worth it.

[Lumpy Taters]

I have a 2007 with a 6.0 that is sitting at 200k now.  It used about a half a quart every 5k miles.   Since 180k it is up to a full quart every 5k.  I don't think the AFM has anything to do with it on my truck but I do know that at 70 mph on the freeway its in 4 cylinder mode getting me a few more mpg.  I know of a few who disabled the AFM and claim performance gains but not any mpg gains additionally most people who build these don't like the AFM and eliminate it when rebuilding one of these.  I will tell you that if you put aftermarket exhaust on one and it switches to 4 cylinders, it sounds like crud and the droning will drive you mad.

[3cityhuntr]

Had an 07 I bought brand new, always changed oil at 3-4K (70% life remaining) so figured I would not have an issue.  Almost like a light switch Started burning a quart every 1k at 65k.  Truck was 7 years old so outside of warranty by years.  Service writer told me it was a known issue at the time and Chevy would do nothing for me.  Traded it for a 14 tundra and will never go back.  Realize that all AFM type systems (Chevy/dodge) have the same issue.  Chevy ruined the 5.3 by adding that garbage to it (of course the government is driving them to).  You’re smart to disable it, hopefully you won’t have any issues.