Any lifter failures in 5.3 without DFM

Nutmeg · December 31, 2021

Was interested if any of the trucks shipped without DFM have had any lifter failures? Understand they have all the same mechanical parts so am concerned as I have a 2021 Sierra with a May build date. Outside the known date but since the hours were high compared to the miles thinking it may have been one that was idle tested.

milkmaster · January 1, 2022

Not so far! Only 5k miles though. Built in June 21

Edited January 1, 2022 by milkmaster

Supreme Pizza · January 1, 2022

12 hours ago, Nutmeg said:

Was interested if any of the trucks shipped without DFM have had any lifter failures? Understand they have all the same mechanical parts so am concerned as I have a 2021 Sierra with a May build date. Outside the known date but since the hours were high compared to the miles thinking it may have been one that was idle tested.

Yes.

Flatblack83 · January 1, 2022

There have been quite a few, its hit and miss. They did a poll on face book, it seemed like 10% have had problems with lifter failure and an occasional bent pushrod. The mileage goes all over too, from 50 miles to 120k..lol

Nutmeg · January 1, 2022

13 hours ago, Supreme Pizza said:

Yes.

Well that kills a couple of the theories. Do you know if they are using the standard DFM lifters as replacement or a different design since the DFM is not active.

haider320 · January 2, 2022

Build date 10/21 and no DFM. I only have 1100 miles on the truck though. So far so good. Fingers crossed...

Byrds8 · January 3, 2022

Build date 7.21, no DFM and 2500 miles. So far so good. Hope like hell it doesnt break. Sad this is something that has to be a concern.

newdude · January 3, 2022

On 12/31/2021 at 1:07 PM, Nutmeg said:

Was interested if any of the trucks shipped without DFM have had any lifter failures? Understand they have all the same mechanical parts so am concerned as I have a 2021 Sierra with a May build date. Outside the known date but since the hours were high compared to the miles thinking it may have been one that was idle tested.

Have yet to see any with failure.

On 1/1/2022 at 1:29 AM, Supreme Pizza said:

Yes.

Got any examples of lifter failure of a factory DFM disabled truck? We've sold a bunch, some over 10K on them, no failures.

On 1/1/2022 at 2:58 PM, Nutmeg said:

Well that kills a couple of the theories. Do you know if they are using the standard DFM lifters as replacement or a different design since the DFM is not active.

No. Same mechanicals. ECM is missing the parts to operate DFM.

Edited January 3, 2022 by newdude

Nutmeg · January 4, 2022

Good to hear some positive news. Have 2k on mine and want to see a whole lot more. Have a oil pressure question. My 5.3 no DFM from factory, has 90 lbs oil pressure on a cold start, normally runs down the road just below 60, and drops to 30 or a hair under at idle. Is this what others have seen on theirs?

lebag335 · January 4, 2022

9 hours ago, Nutmeg said:

Good to hear some positive news. Have 2k on mine and want to see a whole lot more. Have a oil pressure question. My 5.3 no DFM from factory, has 90 lbs oil pressure on a cold start, normally runs down the road just below 60, and drops to 30 or a hair under at idle. Is this what others have seen on theirs?

Yes

Steve-2019 · January 4, 2022

13 hours ago, Nutmeg said:

Good to hear some positive news. Have 2k on mine and want to see a whole lot more. Have a oil pressure question. My 5.3 no DFM from factory, has 90 lbs oil pressure on a cold start, normally runs down the road just below 60, and drops to 30 or a hair under at idle. Is this what others have seen on theirs?

Normal

Diamond817 · January 7, 2022

2021 5.3 with DFM here and 20,000 mls. No issues.

Stifler · January 7, 2022

OK I will be the dummy... there are 21s with no DFM? or are you talking disabled with a tuner? How do you know if you have or dont have DFM?

WeGone · January 7, 2022

You can check the RPO codes, I also read its on the window sticker as a $50 credit. Check some of the older posts about it they list what to look for.

Try this for starters.

Edited January 7, 2022 by WeGone