My understanding of the GM 5.3L or 6.2L with the Active Fuel Management (or other names of similar systems) is that they have been very problematic. Is that still true on the direct injected engines 2015 and up? If so, is there a way to make them reliable ie permanently shut off that system? I will be looking for a later model Silverado or Sierra soon, probably 2015-2020 range and would rather avoid problems. Is the direct injection an issue with these engines ie intake valve deposits or serious fuel dilution or have they figured a way to avoid that without regular cleanings and oil changes?
GM displacement on demand or active fuel management systems
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Some of our fleet trucks have suffered from valve and runner deposits and excessive pinging under load.
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If it's any consolation, it's not just GM that has experienced engine trouble with such systems.
I don't know for sure, but tow/haul mode may disable or reduce it.
I don't know for sure, but tow/haul mode may disable or reduce it.
AZjeff
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You can disable it but all of the hardware is still in there. I spent a bunch of time on GM truck forums before I bought the '16 Silverado and it's a dice roll if your engine parts will live a happy life together no matter what you do. The Ecotec3 engines from 2014-18 were better than earlier and did 8-6-4 deactivation. From 2019 up they call it dynamic fuel management and can turn off up to 7 and run on 1 cylinder and apparently randomize which ones turn off to spread around the wear. I haven't paid attention to this latest generation of monkey business to hear how it's doing.
Rumor was with earlier gens T/H mode and M5 would disable it but don't know about these latest gens.
Conservative OCIs and good oil to keep all that extra stuff really clean is thought to help. It's not a huge problem.
Rumor was with earlier gens T/H mode and M5 would disable it but don't know about these latest gens.
Conservative OCIs and good oil to keep all that extra stuff really clean is thought to help. It's not a huge problem.
That was my next question. Is there evidence that robust oils make a difference? I would use either Pennzoil Platinum or Rotella gas truck synthetic oils and probably a Fram Ultra Guard filter. Is that likely to prevent the lifter issues, or is there not enough evidence to determine that.
Ironical enough there have been less issues with the new dynamic engine mgmt than there have been with AFM. However-the AFM issues are not that widespread. The Internet made it sound like there were thousands of motors self destructing. I have had three AFM motors with no issues.
I have had three AFM trucks (2010,2015,2018), I don't put many miles on them; the most was around 45,000 miles on the 2010. I have had no problems. My current Silverado, a 2018, has 29,000 miles. I recently purchased a Range Technolgy AFM disabler. I wish I had bought one years ago. The 4 to 8 and back switching is annoying to me. I would usually put the transmission in manual mode, (which disables AFM but limits the top gear to 5th) but that got tiresome after a while. Tow/Haul mode doesn't disable it either. It will switch to 4 cylinders when towing (and that is really annoying!). My issue isn't with the longevity of the system, but the operation.
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I mean, yeah they can fail. Oil changes aren’t going to help much (IMO), in all honesty, it’s how frequently you have the AFM working and engaging. I’ve found that the more it engages, the more wear occurs at the pin ramps/groove in the collapsible lifters. You can tune that off though. Honestly I think the 6 cylinders switch into V4 much less and are a smoother ride. I know that sounds funny but I’ve driven both (and owned a 2018 5.3 V8), the V6 models run smoother because they switch in to V4 less.
But I would not call it as wide spread as it used to be. Like I said, if it turns on and off a lot it can wear. If you drive very conservatively it’ll activate more often, if not? You’ll stay in V8 mode more, plus you can tune it off. But I’m not seeing a lot of failures regardless. Some, but not a ton. They are having fuel injector issues. Misfires. That’s an issue. But I wouldn’t call valve coking a big issue with these engines compared to other engine. It does happen but not like the old Audi Direct inject engines from ten years ago. You can easily install a catch can and the manifold is easy to remove if you want to manually clean the valves at 100k or so.
But I would not call it as wide spread as it used to be. Like I said, if it turns on and off a lot it can wear. If you drive very conservatively it’ll activate more often, if not? You’ll stay in V8 mode more, plus you can tune it off. But I’m not seeing a lot of failures regardless. Some, but not a ton. They are having fuel injector issues. Misfires. That’s an issue. But I wouldn’t call valve coking a big issue with these engines compared to other engine. It does happen but not like the old Audi Direct inject engines from ten years ago. You can easily install a catch can and the manifold is easy to remove if you want to manually clean the valves at 100k or so.
ls1mike
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The range will help with the longevity of the Transmission/Torque converter. Less going into and coming out of lock up. There is the added benefit of not shifting in the 4cyl, but as Jeff said the components are still in there. Seems no rhyme or reason as to why they fail on a particular truck.
I had AFM on the Caprice and used the Range for a year. It worked well, but I was happy to do a cam swap and get rid of all the AFM/DOD stuff. A full delete with dyno tune, if you do it yourself with quality parts is about 2000 to 2500. Having some local shop do it maybe 3500 to 4000 dollars.
I had AFM on the Caprice and used the Range for a year. It worked well, but I was happy to do a cam swap and get rid of all the AFM/DOD stuff. A full delete with dyno tune, if you do it yourself with quality parts is about 2000 to 2500. Having some local shop do it maybe 3500 to 4000 dollars.
There is not evidence of that.
There was one guy last year on the Silverado forums with a new AT4 6.2l that had less than 2,000 miles on it and it ate some of the lifters already. Flip side, guys with 200-300k miles and no issues. So yeah.
So high or low ambient temperatures, dry or humid or wet, daily driven or sits for days before diving again, different oils etc...non of that seems to matter? The only reliable metric is how often it activated/de-activated which caused wear? Why does it wear, most regular lifters can go hundreds of thousands of miles without failing due to wear. Would suplimental moly help with the wear issue whether the system is disabled or not? Upon buying a truck (when I find a nice used one 1-5 years old) the first thing I will do is disable the system, but with all the parts remaining can issues still arise with that system and those lifters, or will disabling it stop the damaging wear (and help save the TC clutches).
I do not thoroughly understand exactly how the system works, or the differences between the different model year changes, or exactly what the lifters do when active or inactive, which is why I am asking so many questions. Seems to me when a lifter collapses to keep the valves closed, why doesn't it make a lot of clackety clack lifter noise as the push rod would have a lot of slack in it.
I do not thoroughly understand exactly how the system works, or the differences between the different model year changes, or exactly what the lifters do when active or inactive, which is why I am asking so many questions. Seems to me when a lifter collapses to keep the valves closed, why doesn't it make a lot of clackety clack lifter noise as the push rod would have a lot of slack in it.
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I wish there was more info on the failures such as oil used when it failed, OCIs, etc. it does seem like the problems are infinitely less on the 2011+ vehicles. That’s when they changed to the new valve cover/updated PCV design and the AFM shield in the oil pan. Those two changes seem to have made a drastic difference.
Yes-good information here. I would suggest that most who buy $50,000.00 pickups at the minimum follow the OLM. I don't think type of oil makes any difference in the failure rate.
The AFM system activates within a very narrow window of operation. if you feather the pedal trying to squeeze MPG that system will toggle multiple times per mile. From a mechanical perspective this is wear and tear. If you lead foot or tow a load the system will not toggle nearly as often for much less wear and tear. IMO a collapsed lifter has a better chance of pumping back up successfully with more stout oil in the engine than 0w20. I use 15w40 in Arizona.
17 - 6.2l, Ive had injectors replaced 2 times under warranty I believe they get leaky and you can see evidence in uneven fuel trims Bank1 vs Bank2. Cold starts is where misfire error codes started. I started to run Gumout PEA at each oil change in hopes it keeps them happier going forward. Time will tell.
I added a good Catch can early on to possibly avoid valve issues and it gets a few ounces between oil changes. If i used the 0w20 oil i figure there would be much more chocolate goo in there to dump. the jury is still out wether it makes a difference till I open it up and look. So far no problems.
17 - 6.2l, Ive had injectors replaced 2 times under warranty I believe they get leaky and you can see evidence in uneven fuel trims Bank1 vs Bank2. Cold starts is where misfire error codes started. I started to run Gumout PEA at each oil change in hopes it keeps them happier going forward. Time will tell.
I added a good Catch can early on to possibly avoid valve issues and it gets a few ounces between oil changes. If i used the 0w20 oil i figure there would be much more chocolate goo in there to dump. the jury is still out wether it makes a difference till I open it up and look. So far no problems.
Barring any mistakes any shop/garage is going to use a Dexos spec'ed oil. There isn't any conventional oil that meets this specification. However-there are blends that dealers use that meet the spec. They will give you a choice many times based on price point. I know it seems hard to grasp on BITOG-but there are many who do regular oil changes at a shop or dealership-with the vast majority of times it done correctly.
Also-even if an incorrect oil is used for one OCI-the motor will not blow up. Most guys who have a $500.00 or $600.00 truck payment kind of want the vehicle to last until it's paid for.
You mentioned Conventional Oil, that would be an INCORRECT OIL since none meet the Dexos spec.
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