2013 GMC Yukon Denali - bad lifter?

[pmckrotch]

I have a 2013 GMC Yukon Denali XL. 250,000KM about 155,00miles (No CEL)

Just this morning I started hearing this knocking noise on driver side (video below)

The vehicle has had religious oil changes with Synthetic, and transmission flushes.

The only difference is yesterday I filled it with E91 Premium, and the noise appeared this morning.

Hoping this isn't a lifter?

 

[Dustin Jackson]

That sounds like a lifter to me. Best to open it up and find out for certain!

 

[lightflyer1]

Sounds sort of like mine was. Stop running it and repair before it gets worse. Mine bent #4 intake pushrod but the cam and bearings were still good. Replaced just the pushrods and lifters and trays with original and runs very well now. OBDII AFM disabler in place now. Going to send the ECM in for programming to get rid of the AFM and remove the OBDII disabler.

 

[swathdiver]

This is usually a collapsed lifter and maybe a bent pushrod. But you know what? I had an exhaust leak that sounded like that once!

Pull the rocker cover on the offending side and check the valvetrain. Were you using Mobil One's regular full synthetic oil?

 

[Geotrash]

I have a 2013 GMC Yukon Denali XL. 250,000KM about 155,00miles (No CEL)

Just this morning I started hearing this knocking noise on driver side (video below)

The vehicle has had religious oil changes with Synthetic, and transmission flushes.

The only difference is yesterday I filled it with E91 Premium, and the noise appeared this morning.

Hoping this isn't a lifter?

I'll add my voice to those saying it's a collapsed lifter - most likely an AFM lifter on either 2, 3, 5, or 8 (The AFM cylinders).

You have a few options. There is a tool and trick to get it unstuck that works for lots of folks, for a while at least, until they can get in there and mechanically delete the AFM system.

Are you handy and want to tackle this yourself? If so, you've come to the right place. Many of us have done full mechanical or at least partial (electronic) AFM deletes on our trucks and will be happy to help you. If you want to have a shop do it, that's fine too, but it's time for a tow and plan on a $3-7K repair bill, depending on what they find and recommend for solutions.

 

[pmckrotch]

I'll add my voice to those saying it's a collapsed lifter - most likely an AFM lifter on either 2, 3, 5, or 8 (The AFM cylinders).

You have a few options. There is a tool and trick to get it unstuck that works for lots of folks, for a while at least, until they can get in there and mechanically delete the AFM system.

Are you handy and want to tackle this yourself? If so, you've come to the right place. Many of us have done full mechanical or at least partial (electronic) AFM deletes on our trucks and will be happy to help you. If you want to have a shop do it, that's fine too, but it's time for a tow and plan on a $3-7K repair bill, depending on what they find and recommend for solutions.

I'm not that handy, I ended up getting it towed to the shop this morning. Thanks for the info. I will look into the AFM delete after it's fixed.

 

[Ibustbravo]

Yea, the DOD kit in your engine tore up.. It's tear-down time. I rebuilt and installed an engine in my yukon last week. They rebuild easy and go in just as smooth. It's not a bad job at all. It took me three 8 hr days to reinstall to completion. Book hrs are 25.7hrs for removal and reinstall. Seems low, glad I'm not a line mechanic anymore, I'm slow as hell. I'd go broke.

I was able to hand it off to my wife immediately after I finished tho..

I'd suggest getting an alldata.com DIY subscription. $20/mo.. Its a huge time saver.

Chad

 

[Dustin Jackson]

@pmckrotch If they are going to "fix" the problem make sure they use a new VLOM, new lifter trays, and new lifters... and maybe a new cam too.

I recommend you have them FIX it by deleting AFM altogether right now, not deleting AFM after they "fix" it...

 

[lightflyer1]

I'll add my voice to those saying it's a collapsed lifter - most likely an AFM lifter on either 2, 3, 5, or 8 (The AFM cylinders).

You have a few options. There is a tool and trick to get it unstuck that works for lots of folks, for a while at least, until they can get in there and mechanically delete the AFM system.

Are you handy and want to tackle this yourself? If so, you've come to the right place. Many of us have done full mechanical or at least partial (electronic) AFM deletes on our trucks and will be happy to help you. If you want to have a shop do it, that's fine too, but it's time for a tow and plan on a $3-7K repair bill, depending on what they find and recommend for solutions.

I thought they were 1,4,6,7

LS Engine Tech – Active Fuel Management (AFM)

help.summitracing.com

Lifters - AFM engines use special lifters for cylinders 1, 4, 6, and 7. They are taller and have special oil holes.

 

[Geotrash]

I thought they were 1,4,6,7

LS Engine Tech – Active Fuel Management (AFM)

help.summitracing.com

Lifters - AFM engines use special lifters for cylinders 1, 4, 6, and 7. They are taller and have special oil holes.

You're correct! Note that they have the image of the L94 block is taken from the rear on that page, which is where I got my reference for my post. The AMS image below is taken from the front with the AFM towers on the 1,4,6,7 cylinders. Thanks for the catch!

Summit site (taken from the rear)


AMS racing site (taken from the front)