Does anyone know the exact failure mechanism of the lifters?

[Dogged]

I've got almost 24k on my 2021 with no problems, but I typically run 150k+ miles between trucks. Has there been any actual info on what is failing and if we as owners can do anything to help prevent it?

These new trucks are calling for 0-20 oil which is super light, especially in hot weather and towing. Most likely so light to squeak out 0.001 MPG, probably at the long term expense of the engine. Maybe slightly heavier oil grades in the summer would be advantageous and provide better mechanical wear resistance? FYI, the 2020 6.2 calls for 5-20.

I'd love to know what's truly happening to feel better about long term ownership on this one.

 

[Fireman591]

Turning off the DFM would sure help. It is when those inactive cylinders fire up at just the wrong time that a push rod gets bent. The push rods are making contact with the lifter sidewall and causing harmonic bending of the push rod. If that cylinder happens to fire up when that push rod is already flexed it will get flexed into a permanent bend. Wear marks on the lower push rod just above the seat confirms the contact. Major design flaw compounded with the DFM system.

 

[Tiki]

I am a firm believer in more frequent oil changes as a strong preventative measure. I notice less noise overall going to ~50% on the OE system wear number.

 

[Micahsd]

There’s a TSB out that talks about how the bad lifters could be in vehicles built between Sept 2020 and March 2021.

Mine was built March 19th and so far no issues although I’m almost to 5,000 miles. Sounds like most fail between 5-12k miles.

 

[iamdub]

Turning off the DFM would sure help. It is when those inactive cylinders fire up at just the wrong time that a push rod gets bent. The push rods are making contact with the lifter sidewall and causing harmonic bending of the push rod. If that cylinder happens to fire up when that push rod is already flexed it will get flexed into a permanent bend. Wear marks on the lower push rod just above the seat confirms the contact. Major design flaw compounded with the DFM system.

Can the push rods be replaced with stronger aftermarket ones? Mine's an archaic 4th gen, but I got some .080" wall push rods in the largest diameter that'd fit (3/8") for mine when I needed some custom-length ones for my build. I did this just because the stock ones in the 3rd- and 4th-gen engines are a known weak link, even in a stock engine.

 

[avalonandl]

That is not much clearance on that pushrod——

 

[iamdub]

That is not much clearance on that pushrod——

It's not. But, it shouldn't flex. Not with .080" chromoly wall and my mild cam.

I still need/want to upgrade the trunnion bearings. When I have the rocker covers off, I'll inspect the push rods to see it they've been contacting. I might pop a cover off at the next oil change.

 

[avalonandl]

There is no pushrod that doesn't flex some. If you had high speed cameras you would be amazed the amount of deflection at 6,000 rpm.

 

[iamdub]

There is no pushrod that doesn't flex some. If you had high speed cameras you would be amazed the amount of deflection at 6,000 rpm.

I meant flex enough to contact. Regardless, you're right and it's still something I should check sooner than later. It sees 6000 RPM almost every time I drive it.

 

[Fireman591]

Pushrod Upgrade 2014-2018+ | Crazed Performance R

This is a pushrod upgrade for those having or concerned about having a bent pushrod issue in LT based platforms. It is a slightly smaller diameter then stock with a much heavier .080 in wall made from 4130 chromoly. This will reduce risk of interference while being stronger then stock. This...

www.crazedperformancerepair.com

 

[Joeltz]

I've got almost 24k on my 2021 with no problems, but I typically run 150k+ miles between trucks. Has there been any actual info on what is failing and if we as owners can do anything to help prevent it?

These new trucks are calling for 0-20 oil which is super light, especially in hot weather and towing. Most likely so light to squeak out 0.001 MPG, probably at the long term expense of the engine. Maybe slightly heavier oil grades in the summer would be advantageous and provide better mechanical wear resistance? FYI, the 2020 6.2 calls for 5-20.

I'd love to know what's truly happening to feel better about long term ownership on this one.

Here is what my lifter did … it Stuck in DOD…. Dead on Demand…. A Texas speed Dod removal kit… Cam and lifters and plugs for the Dod. AND a Dyno Tune Emm reprogram !!! See 24 mpg at 67 now.

 

[Bob2C]

I am a firm believer in more frequent oil changes as a strong preventative measure. I notice less noise overall going to ~50% on the OE system wear number.

3-4k mile intervals for me. I have seen YouTube videos where the bad lifters were caked up which leads me to believe poor maintenance. Once those small oil ports get clogged. Game over. I also run either amsoil or liqui Molly engine flush every 10k or so. I know some here would cringe at a flush but I think it’s harmless. I also tuned out AFM. Is all this going to prevent failure, who knows but at least it’s something. Some never have an issue and just drive their vehicles. I guess part of is luck too

 

[DCRich]

There’s a TSB out that talks about how the bad lifters could be in vehicles built between Sept 2020 and March 2021.

Mine was built March 19th and so far no issues although I’m almost to 5,000 miles. Sounds like most fail between 5-12k miles.

My Tahoe was built end of March 2021 and the dreadful ticking noise and misfiring just occurred three days ago at 6,300 miles. Hopefully, you do not have the same result.

 

[Micahsd]

My Tahoe was built end of March 2021 and the dreadful ticking noise and misfiring just occurred three days ago at 6,300 miles. Hopefully, you do not have the same result.

Ugh…that’s sucks.

Good luck with the repairs. Hopefully it goes well.