AFM Disabler Question

[GN2018]

Thinking about getting a Range AFM disabler.  The question I have is, will it matter.  Will it help to keep the top of the engine from a catastrophic failure.  Or, is the equipment in the engine that allows for AFM, like the lifters, basically flawed and prone to failure due to being engineered to support AFM.

 

Along those lines, I’m also wondering if it would be prudent to have some of the engine components swapped out in order to prevent a catastrophic failure.  My thinking is that even though an equipment swap would be expensive, it would be less expensive than a catastrophic failure which would have collateral damage.

 

Or, should I just ride out my extended warranty (two more years) and trade in my truck?

[CamGTP]

I tuned mine out nearly 7 years ago, all of the parts are still in the engine and haven't been activated since. Sure the parts are still there but the likelyhood of a failure is way less because the system is turned off. I bet my truck could go another 7 years without much of a worry and I drive my truck kinda hard.

 

Doing a delete with hard parts and tuning is very expensive on the 2019+ trucks. The work is the same if you replaced the DoD parts or if you removed them and installed different parts. So that labor is going to be the same. The added cost of tuning kinda makes it not worth it. Buying a new used engine or new short block might even be cheaper to be honest with how high labor rates have gone at some places.

[Bikerjon]

On 9/13/2025 at 10:06 PM, GN2018 said:

Thinking about getting a Range AFM disabler.  The question I have is, will it matter.  Will it help to keep the top of the engine from a catastrophic failure.  Or, is the equipment in the engine that allows for AFM, like the lifters, basically flawed and prone to failure due to being engineered to support AFM.

 

Along those lines, I’m also wondering if it would be prudent to have some of the engine components swapped out in order to prevent a catastrophic failure.  My thinking is that even though an equipment swap would be expensive, it would be less expensive than a catastrophic failure which would have collateral damage.

 

Or, should I just ride out my extended warranty (two more years) and trade in my truck?

I have used the Range Technologies DFM disabler on 3 T1s. 2021 and 2023 with 5.3 and 2025 w/6.2. They all worked perfectly. There are some people who think if you have the collapsible lifters that they will fail regardless but i don't believe that. I have been a Master Technician for over 35 years. My advice to you is get the Range disabler and don't worry about the lifters. By the way this also disables auto stop/start which most people hate.

[BlueV8]

I’d be careful about treating any AFM/DFM disabler as a lifter-failure guarantee. It can change cylinder-deactivation behavior, but it is not a mechanical repair and it does not remove the collapsible lifters from the engine.

The other big thing is year/platform. A 2021 truck, a 2023 truck, and a 2025 truck should not automatically be grouped together for plug-in fitment. Exact year, engine, transmission, and refresh status matter.

[SilveradoMarc]

Wouldn't swapping out the original AFM/DFM parts for a complete Delete Kit be the best route to go if one could afford to go that route?

[GN2018]

From what I’ve read, yes, that would be the best thing to do.  However, it is very expensive and there’s no guarantee that the lifters will actually fail, especially if you’re not going to keep the truck for its entire useful life.  My plan is to wait until I hear a lifter go bad and hope I can catch it without it being a catastrophic failure.  At that point, they have to open up the engine anyway so that’s when I’d mechanically eliminate the AFM.

 

Plus, there is a 5 year 60K mile warranty on the drive train.  I have an extended warranty so I’m good until March of 2027, so I’m certainly not doing anything mechanical before then.  I do have the Range disabler and I change the oil way sooner than suggested hoping that will get me into the 100K mile mark at which point, I may sell the truck.  I don’t drive much.  My ‘21 has 48K miles on it so to get to 100K miles will probably take another 5 years.  Probably more because I drive less now than the first few years of ownership.

[diyer2]

The lifter issue can be dealt with by shorter oil changes and quality oil IMO.

Edited July 18 by diyer2

[BlueV8]

A complete delete is the most thorough mechanical solution, but it is also major engine work. On a quiet truck that is still under extended warranty, opening the engine purely as prevention is difficult to justify.

A plug-in disabler stops commanded cylinder deactivation, but it does not remove or repair the collapsible lifters, so it should not be treated as failure insurance.

I would keep the oil full, document the maintenance, and have any persistent tick, misfire, or loss of power diagnosed promptly. If the engine eventually has to come apart, that is the logical time to compare an OEM-style repair with a complete delete.

The right choice depends on the truck’s symptoms, warranty status, expected ownership period, and whether the engine already needs to be opened. We explain that decision in more detail here—full disclosure, this is our own guide:

https://www.bluev8.com/blogs/news/do-you-actually-need-an-afm-disabler

 

One exception: some 2021 L82/L84 trucks have RPO YK9, meaning cylinder deactivation was already disabled in the factory ECM; on those trucks a plug-in disabler is redundant, although the AFM/DFM hardware remains inside the engine.

[KARNUT]

2 hours ago, diyer2 said:

The lifter issue can be dealt with by shorter oil changes and quality oil IMO.

I’m doing an experiment on a vehicle I don’t have much money in. I’m going by the premise that after they last 100K miles they were no mechanical problems with assembly. Or defects with the parts. With oil changes by the minder for the first 127K miles when I acquired it. I quickly went through low mileage oil changes then settled on 5k oil changes with close to 170K miles on the vehicle currently. I did have the option to turn off the cylinder deactivation. I didn’t on this vehicle because it’s in ECONOMY mode at least half the time. It should be a no brainer frequent oil changes are the key. The manufacturer gets away with the long oil changes with its severe service  maintenance. Just ask them what is normal. 

Edited July 18 by KARNUT

[Grumpy Bear]

Melling I believe is/was the OEM on the lifters who explored this problem some years ago. The white paper they generated on the topic indicated two items of note when I read it. 1.) They only fail on the switch. Prevent the switch, prevent the failure. 2.) The majority fail due to deposits messing up the timing of that switch. Anyway that's what I got from it. 

 

Mine have always been active, 195K+ now, and my oil maintenance is surgically clean. 

 

Of course this assumes good parts. That is no heat treat issue or machining flaws. I get comfortable that these issues are in the rearview mirror by about 30K. IMHO naturally. 

[GN2018]

Just looked up my records.  I've never gone over 5000 miles between oil changes.  At 46K miles, I have 10 oil changes.  I hope that will help.  I also installed the disabler last year.  I've still had a few times when it didn't seem to engage (which I can tell because the start stop feature kicks in), but for the most part, I think it's working.  For some reason, GM did not include the number of cylinders running in the information screen like I had on other models.  In my Cadillac, it shows me when it's running on 4 cylinders on the fuel milage screen.  I can't find that on my '21 Denali.