Buying pre-owned, is turning the AFM off at 60k usually too late?

Mambo Dave · October 11, 2015

I'm very wary of the 5.3L with AFM, and am wondering what the consensus is of buying a pre-owned with 40k to 60k miles on one that has had the AFM going the entire time, but only then shutting it off?

Would the damage be done and the funky lifters most likely worn?

Criscone · October 12, 2015

AFM being the 4cyl/8cyl deal? If so I don't see why it would hurt anything?

Tek74 · October 12, 2015

Just out of curiosity......are you going to shut off the AFM with a Tuner or with the $200 Range Technology device?

Welder2014 · October 12, 2015

Just my opinion would leave it alone. On my 5.3 14 the afm works great love this engine at 12000 miles no problems.

TheTunaHunter · October 12, 2015

23,000 miles in 16months with a virgin ECU/ no AFM disable and couldn't be happier. City mileage is crap but I'm all smiles with a 22mpg average on the highway. The best I've ever seen was 26.8avg..

TJay74 · October 12, 2015

The AFM on the new DI engines have zero issues like the previous engines, even still I turned mine off as it very rarely went into AFM mode. I still get 17 in the city and up to 21 on the highway with my 6.2l.

TxTruckMan · October 12, 2015

I'm very wary of the 5.3L with AFM, and am wondering what the consensus is of buying a pre-owned with 40k to 60k miles on one that has had the AFM going the entire time, but only then shutting it off?

Would the damage be done and the funky lifters most likely worn?

There's been no issues with AFM so far, so it's not really possible to answer your question. Of course, there probably aren't a lot of 2014 trucks with that many miles either. I guess I would say that it's never too late, but I also agree with everybody else here that there doesn't appear to be a reason to turn it off. I have no concerns with AFM.

tnchevy · October 12, 2015

I am only at 8k miles but I have been pleased with the AFM but had my doubts before I bought the truck. Mine actually stays in V4 more than I thought it would. The only time I can tell I am even in V4 is when the throttle is barely pressed when cruising down a highway, the truck has a very slight shake and a slightly different noise. This was exaggerated when I put on a Dynomax VT muffler, the main reason I took it off and went back to stock. i assume it is a back pressure thing.

Poltergeist · October 12, 2015

61k in less than 2 years with no issues due to AFM or anything else for that matter.

crafferty · October 13, 2015

My 2014 has 10,650 miles on it right and will be getting it's second oil change later today or tomorrow. To date I have zero oil consumption issues and the truck has ran flawless as expected. Personally I don't believe the AFM to be nearly as bad as people make it out to be. Online on forums it looks like the worse thing possible but I have tons of buddies and co-workers with 07.5-13 trucks with AFM and zero issues. Majority of them are higher mileage as well.

Potts · October 13, 2015

I agree - I love the AFM. It's butter smooth to where I can barely tell its switch between 4&8 cylinders 95% of the time. If I'm not looking at the indicator I'd probably have no idea 99% of the time. I know that doesn't answer your question really, but my point is it's a great feature and if I were you I'd keep it enabled. If you're really worried, I'd be more focused on getting a good warranty on the drivetrain when purchasing.

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Mambo Dave · October 13, 2015

Just my opinion would leave it alone. On my 5.3 14 the afm works great love this engine at 12000 miles no problems.

Ok.

Mambo Dave · October 13, 2015

There's been no issues with AFM so far, so it's not really possible to answer your question. Of course, there probably aren't a lot of 2014 trucks with that many miles either. I guess I would say that it's never too late, but I also agree with everybody else here that there doesn't appear to be a reason to turn it off. I have no concerns with AFM.

Thank you.

Here I thought that all the stories of the not-so-old 5.3L lifters needing replaced were due to the motor wearing out the lifters by going in and out of V4 AFM mode.

So if that isn't it, what is causing all the 5.3L troubles with lifters needing replaced?

I really don't want to have to get to a point at just over 100k miles where I have to take the heads off just to get to the lifters. Amazon sells a lifter replacement kit because it's so prevalent: http://www.amazon.com/Lifter-Replacement-Gasket-Bolts-Lifters/dp/B00LXBLTSW

brokesilverado · October 14, 2015

A vendor at my work has a 14 gmc Z71 cc with the 5.3 He has 85,000 miles on it. It's his work truck & his personal truck so drives it alot. He has no problems with oil consumption or v4 mode either one.

TxTruckMan · October 14, 2015

Thank you.

Here I thought that all the stories of the not-so-old 5.3L lifters needing replaced were due to the motor wearing out the lifters by going in and out of V4 AFM mode.

So if that isn't it, what is causing all the 5.3L troubles with lifters needing replaced?

I really don't want to have to get to a point at just over 100k miles where I have to take the heads off just to get to the lifters. Amazon sells a lifter replacement kit because it's so prevalent: http://www.amazon.com/Lifter-Replacement-Gasket-Bolts-Lifters/dp/B00LXBLTSW

That kit is for the older engines - gen 4. The new gen 5 engines have been completely redesigned and share no components with the old engine.