Kilgore Trout

You might want to get a second opinion. I can't imagine a rod failure because of anything with DFM.

My brand new '21 Sierra does it, sounds like the fuel pump priming, but if not that, something spooling up. Normal. My old '07 Yukon has "spooling up" sounds when I open the driver's door. The CD starts searching, etc. They have been doing things like this for a long time.

Holy smokes that is beautiful. That looks better than my stock AT4 bumper. I think I will have to have one of those.

You might check your local marine supply. I would think one of those high amperage boat battery isolator switches would work fine. Just have a battery shop modify your cables to allow the switch to be installed in line to your negative terminal and you could disconnect the battery by the turn of the switch.

I just bought a 2021 Sierra 6.2L. I will be changing my own oil. I had a long talk with the service advisor I have known at my local dealer for a very long time. I asked him about the lifter issues on these late model engines and he confirmed it is real and a problem. I own a 2007 Yukon 5.3L that I bought new, am well into six figures mileage wise, I have changed my own oil most times at 5K intervals, Valvoline Full Synthetic 5W30 and WIX filters. When I didn't change it myself, I had it changed at my dealer. I have never had an AFM lifter fail, but I did tune out AFM recently, just in case. Getting back to newer DFM design and problems, the service advisor stated that they have had a number of customer trucks that needed new lifters. He said almost all the failures of 2021 model year trucks had initial failures before 8K miles. He maintains one company's fleet vehicles and he said they had extremely high failure rates (like half) and they were all early examples of the 2021 MY. He said early on they replaced just the failed lifters or a single bank, and everything else looked OK, so put the truck back into service. Of the units they changed one or just one bank of lifters they had an alarming return rate for the same lifter failure issue. He indicated these second time failures almost all happened within the 20K total mileage on the engine window. What I failed to ask him was if the return failures were with lifters that were not changed the first go round (a key fact that would tell us a lot about the source of the problem). He went on to say that they have since made it policy to change all 16 when any lifter failure happens on these late model trucks. He stated if I had a failure of any lifter, they would be changing all 16. I also didn't ask him if his fleet customer that had a high failure rate, if the trucks were acquired during the "bad lifter window" identified by GM, but given it was late 2020, early 2021 is when they bought the trucks, my assumption (at least until I see him again and remember to ask him) is these fleet trucks were produced in the "bad lifter" window. My truck was made in October, so I have my fingers crossed the faulty lifters have been purged from the system. When I asked the advisor if he would do anything special with regard to maintenance, if it was his truck, and he said he would definitely change the oil and filter at 1500 miles, again at 3K miles and then every 5K miles from that point on. He said he would never run one of the AFM/DFM lifter equipped engines to the recommended 7.5K interval. The 1500 and 3000 changes will be a change to my original plan, but the 5K interval is normal for me, so nothing new. I am investigating whether a tune out of the DFM is possible in my PCM. It was a very simple change to my 2007 Yukon SW. I will probably contact a few of the tuners I know who do good work and see if they have cracked the 2021 SW code and can turn the cylinder deactivation off in my new ride. If they can, I will almost certainly do it.