Collapsed Lifter 2010 denali

[thompsoj22]

wish i knew more about this system but in many ways im sooooooo glad i dont have it. i was guessing the valley cover and it's components as it controls the lifters somehow?

 

[swathdiver]

they said they did test it and the test were good which is weird why they are saying it is bad now. what is a tech-2 how much do they run?

The Tech-2 was GMs standard tool to work on these trucks, from about 1991 to 2013 (includes these GMT900, even the 2014s). You can pick up a "clone" as they are called for about $350 give or take and they quickly pay for themselves as many can attest. Do a search on this forum to pull up multiple posts on them.

 

[swathdiver]

wish i knew more about this system but in many ways im sooooooo glad i dont have it. i was guessing the valley cover and it's components as it controls the lifters somehow?

The VLOM consists of 4 solenoids that send oil to the lifters to collapse them for V4 mode operation.

If interested, you can download the "restoration kit" on the GM Heritage website for the Suburban and Tahoe and get a detailed explanation about how AFM works and all the other nifty things about the GMT900 platform.

 

[Geotrash]

The VLOM consists of 4 solenoids that send oil to the lifters to collapse them for V4 mode operation.

If interested, you can download the "restoration kit" on the GM Heritage website for the Suburban and Tahoe and get a detailed explanation about how AFM works and all the other nifty things about the GMT900 platform.

Thanks for the pointer - VERY helpful info. Here's the link if anyone needs it.

https://www.gmheritagecenter.com/do...ion-kits/Suburban/2007-Chevrolet-Suburban.pdf

I have 100K on a 2012 with AFM. I keep the oil clean and use a OBDII port-mounted dongle to keep it locked in V8 mode. I also changed the filter screen in the rear oil gallery. Is there anything else I can do to prolong the life of these lifters and cam to reduce the chances of problems later? Any idea how long I can expect the OEM parts to last this way?

Cheers,
Dave

 

[swathdiver]

Thanks for the pointer - VERY helpful info. Here's the link if anyone needs it.

https://www.gmheritagecenter.com/do...ion-kits/Suburban/2007-Chevrolet-Suburban.pdf

I have 100K on a 2012 with AFM. I keep the oil clean and use a OBDII port-mounted dongle to keep it locked in V8 mode. I also changed the filter screen in the rear oil gallery. Is there anything else I can do to prolong the life of these lifters and cam to reduce the chances of problems later? Any idea how long I can expect the OEM parts to last this way?

Cheers,
Dave

You're doing Dave; keep AFM from working, keep clean oil in the motor and that screen clean. Many go 200K-300K while others barely make it to 40K. What we've seen on these forums is that dirty oil is the biggest contributor to failure. Then the failure of the VLOM solenoids and AFM lifters.

 

[Geotrash]

You're doing Dave; keep AFM from working, keep clean oil in the motor and that screen clean. Many go 200K-300K while others barely make it to 40K. What we've seen on these forums is that dirty oil is the biggest contributor to failure. Then the failure of the VLOM solenoids and AFM lifters.

Okay, James - thank you for that. I'll just roll with it hoping they'll go another 100K at least. It should only see 7-8K a year - mostly on the highway.

Looking at the details of how the system works, it's easy to see how just one hesitation in one of the solenoids or the pins in one lifter failing to engage properly at transition time, could hammer a cam lobe in short order. Once you damage a cam lobe, it's only a matter of time. Now I understand WHY it's so important to keep the AFM system deactivated. Thanks again.

 

[swathdiver]

Okay, James - thank you for that. I'll just roll with it hoping they'll go another 100K at least. It should only see 7-8K a year - mostly on the highway.

Looking at the details of how the system works, it's easy to see how just one hesitation in one of the solenoids or the pins in one lifter failing to engage properly at transition time, could hammer a cam lobe in short order. Once you damage a cam lobe, it's only a matter of time. Now I understand WHY it's so important to keep the AFM system deactivated. Thanks again.

One of the less common things to happen is that the lifter trays crack allowing the lifters to spin which then wipe out the camshaft and or lobes and if an AFM lifter, is not in position to collapse a lifter should the computer wish to do so!

I was all set to physically delete mine and then learned that just prior to purchase, the entire system had been replaced with all the latest parts, so we decided to put it off a while and my wife quickly found 1500 ways to spend that money! LOL

 

[Geotrash]

One of the less common things to happen is that the lifter trays crack allowing the lifters to spin which then wipe out the camshaft and or lobes and if an AFM lifter, is not in position to collapse a lifter should the computer wish to do so!

I was all set to physically delete mine and then learned that just prior to purchase, the entire system had been replaced with all the latest parts, so we decided to put it off a while and my wife quickly found 1500 ways to spend that money! LOL

That’s a lucky break! And wives can be good at that

Interesting about the lifter trays cracking as well. Fingers crossed that my hardware is all in good nick for a while.

We love the truck - we’re taking it to Cape Cod from Richmond next weekend. Best rig for family travel I’ve ever owned - the kids LOVE it. I also have a 2007 XL Denali (without AFM) with 200K on it that we keep in Colorado for camping and ski trips.

Dave


Sent from my iPhone using Tapatalk

 

[swathdiver]

We love the truck - we’re taking it to Cape Cod from Richmond next weekend. Best rig for family travel I’ve ever owned - the kids LOVE it. I also have a 2007 XL Denali (without AFM) with 200K on it that we keep in Colorado for camping and ski trips.

Same here, ours love it too for trips and even going out for ice cream. We ran it on the beach in Daytona last week.