Anyone able to chime in about AFM/DFM and lifter failure? I'm hoping it can be disabled if it will prevent lifter failure. Oh and for the record my window sticker says 6.2L ECOTECH V8. No mention about the AFM/DFM.
You are opening a Pandora’s box with this question.
Facts as I know them:
1) In late 2021, GM admitted there was a date range of engines built with potentially faulty lifters in early 2021
2) GM never recalled these engines, but did have some actions related to them, including asking dealers to replace both banks of lifters on any vehicle not yet sold which fell in the date range, replacing both banks on a customer vehicle in the date range if a failure occurred in less than 8k miles (May have been increased to 16k at some point?), and increasing power train warranty to 100k miles on customer vehicles that failed.
3) Some small number of people have had lifter failures more than once.
4) Most people have not had any lifter failures
5) Some vehicles outside the specified date range from GM have had lifter failures (believed to be small number)
6) GM has been using a version of these lifters since AFM appeared in 2009, and has had some of these lifters fail dating back that far. But now instead of them being on 4 of the 8 cylinders (AFM), they are on all 8 cylinders (DFM)
7) There is no known way to “disable permanently” the DFM in the current generation 5.3 and 6.2 L engines, given how locked down the ECU now is. And it is unclear, without a mechanical delete (replacing the collapsible lifters with non collapsible lifters) that there would be an increase in reliability.
Now, what all that means to long term reliability, none of us know. We all have 5 year, 60k mile power train warranty to find out.
Note, I owned a 2013 Suburban with AFM which gave me 115k trouble free miles. It was maintained by the maintenance schedule in the owners manual.
