Question on AFM collapsed lifter failure

bowtiemark · July 21, 2019

On 7/19/2019 at 10:52 AM, MaverickZ71 said:

Unfortunately, it has been an all-too-common problem for many of us.

The most common 'fixes' are:

1) Use a good quality full-synthetic Dexos-rated engine oil in the correct viscosity and quantity, and a good oil filter that's not too restrictive. GM's own Dexos oil, Shell Rotella Gas Truck, and AMS oil seem to be the top-rated oils now. Consider changing the oil more often than the Oil Life Monitor indicates.

2) Consider installing an oil catch can into your PCV system.

3) Turn off AFM via a Range V8 module or PCM tune as soon as possible. Some AFM lifters seem to have a short lifespan, and the more cycles of 8-cylinder mode to less-than-8-cylinder-mode that you subject them to, the more likely they are to fail.

4) Some have even gone so far as to have their engines torn down and rebuilt with an AFM-delete kit from Texas Speed (or such).

5) GM's own documents suggested that Generation 1 AFM saved about an average of 7% on fuel economy. But many of us who deactivated AFM noticed little to no difference in our fuel economy, and some have reported better drivability (no surging with AFM kicking in/out, better transmission shifting, better sounding aftermarket exhaust) with AFM turned off.

full synthetic? why not synthetic? just wondering don’t want to start a whole war on full synthetic vs synthetic lol

MaverickZ71 · July 21, 2019

1 hour ago, bowtiemark said:

full synthetic? why not synthetic? just wondering don’t want to start a whole war on full synthetic vs synthetic lol

When it comes to motor oil these days, there are endless marketing semantics and manufacturer definitions about all of the different base stocks/additives and what constitutes ‘true’ full-synthetic oils. You can seemingly put one drop of man-made synthetic oil into a quart of dead dino oil and legally market it as synthetic oil. There have already been a thousand posts arguing this issue on this website and even more on BITOG and other sites, and since I’m not a petrochemical engineer, I’m not going there.

What I meant in my post is that GM’s original spec for Dexos1 was met by a “semi-synthetic” oil, such as Pennzoil Gold, which was labeled as a synthetic blend with the Dexos approval certification. Since then, GM has upgraded their Dexos spec to require a “full-synthetic” oil such as GM’s own Dexos oil, Pennzoil Platinum, Quaker State Ultimate Durability, or Shell Rotella Gas Truck oil, which are all labeled as full-synthetic oils with the Dexos approval certifications.

Edited July 21, 2019 by MaverickZ71

Doublebase · July 21, 2019

7 hours ago, Trnr1995 said:

2015 Silverado High Country 6.2 60,000 miles. Went to Tennessee on Friday the 12th for vacation. Pulled 2 waverunners down. Came back yesterday with a rental car that I had to pay for. Collapsed lifter. Been a Gm man for 30 years. Not happy. Truck will be there for a couple of weeks. Then go back down from Illinois and get truck and waverunners. VERY Inconvenient. I'm pretty sure me and Gm broke up.

Yeah that would really bother me...I'd be done.

rodney lopez · August 18, 2020

I have a 2019 Silverado 5.3 with 36,000 on it so far i have had the fuel relay replaced ,and at 35,000 the left bank of lifters was replaced due to it malfunctioning ,and i have had a brake pad sensor replaced it was rubbing causing a loud noise when breaking. All these problems has me woundering of the quality of chevy now !

Wc901 · December 31, 2020

Well I followed this thread back in late 2018 when my lifters failed in my ‘16 Yukon Denali at 29k miles. The replaced it and I always knew something wasn’t right. Here we are not even 23 months later and 13k more miles and the same cylinder 6 lifter has collapsed again. So twice the same lifter has failed in uncertain 43k miles. There is a fundamental flaw with this engine. This should be a class action lawsuit.

CSI-WALLEYE · March 24, 2021

On 7/9/2019 at 3:30 PM, 3tspapat said:

So of all of the GMs produced with AFM and is currently out on the road, what is the percentage of ones that have failed so far?

this is the info I would like to have.

Grumpy Bear · March 24, 2021

1 hour ago, CSI-WALLEYE said:

this is the info I would like to have.

Not enough to mount a class action

There is a small percentage of these motors that had actual stress failures due to some manufacturing defect like a heat treat issue. But by and large it's been an issue of oil maintenance. Second post of this tread pretty much nailed it. Last post on that page provided this link:

https://www.melling.com/wp-content/uploads/2018/03/Melling-tech-bulletin-on-GM-LS-Deactivation-Lifter-Issues-3.1.18-1.pdf

You will notice in this pdf says 'miss timed' events. This video will help understand how this happens.

Note in the video he states a failed lifter 'may be' the RESULT of a miss timed even NOT the cause of it? May be means barring a materials failure (material defect) which is VERY uncommon. Also note the comment that oil pressure readings are taken with NEW OIL for verification. That a miss fire can be caused by low oil level, high oil level or anything else that would cause the oil to foam. Water? Fuel dilution? Solenoid failures. Leaking yes but also varnished...sticking.

They can only do so much to keep it idiot proof from idiots.

Edited March 24, 2021 by Grumpy Bear

CSI-WALLEYE · March 24, 2021

25 minutes ago, Grumpy Bear said:

Not enough to mount a class action

There is a small percentage of these motors that had actual stress failures due to some manufacturing defect like a heat treat issue. But by and large it's been an issue of oil maintenance. Second post of this tread pretty much nailed it. Last post on that page provided this link:

https://www.melling.com/wp-content/uploads/2018/03/Melling-tech-bulletin-on-GM-LS-Deactivation-Lifter-Issues-3.1.18-1.pdf

You will notice in this pdf says 'miss timed' events. This video will help understand how this happens.

Thanks for this information. My truck has 30 000 km and the afm works great. Can't feel the switch at all. I am on the fence about deactivation. I don't want to mess with a good thing. I use Ansoil Signature and change it often. I do like to keep my vehicles a long time so I may still deactivate.

Grumpy Bear · March 24, 2021

1 minute ago, CSI-WALLEYE said:

Thanks for this information. My truck has 30 000 km and the afm works great. Can't feel the switch at all. I am on the fence about deactivation. I don't want to mess with a good thing. I use Ansoil Signature and change it often. I do like to keep my vehicles a long time so I may still deactivate.

I have 133,534 on mine trouble free. Long time POA/POE user. Both Red Line and AMSOIL on 5 K OCI's and Purolator One filters or equivalent. I also replace my VLOM filter every 75K. AFM is an expensive fix but so is a spun rod bearing, right?

CSI-WALLEYE · March 24, 2021

14 minutes ago, Grumpy Bear said:

I have 133,534 on mine trouble free. Long time POA/POE user. Both Red Line and AMSOIL on 5 K OCI's and Purolator One filters or equivalent. I also replace my VLOM filter every 75K. AFM is an expensive fix but so is a spun rod bearing, right?

I use redline too. how often do you use it? Also do you change the VLOM filter yourself?

Grumpy Bear · March 24, 2021

11 hours ago, CSI-WALLEYE said:

I use redline too. how often do you use it? Also do you change the VLOM filter yourself?

I change it every 5,000.

I could but I don't. I have a private shop that has earned my trust do it

huskerfan371 · May 4, 2021

I literally just purchased a 2019 Silverado Black Widow edition. Just out of power train warranty and lifter 6 collapsed on my 3rd time driving. (Of course 100 miles from home) This is my 3rd Silverado and I've never experienced this before. Aftermarket warranty company is a hassle and my 1st payment will be due before I likely even get the truck back. What is the best tuner to help prevent (performAFM delete) while also adjusting the speedometer? The 36" tires throw it way off even though they state it has been calibrated by SCA.