Welp…. Ya Fix One Thing…..Dreaded Lifter Tick

Ok. So driving to Fl. All seems to be running wells. I can see a noticeable improvement in MPG. Averaging between 21-23 chilling at 75 mph. Stop at the Buc-Wes in St. Augustine, as I approach the light at the top to make the right I feel a a vibration. Almost misfire like. As I get to the light to turn towards the station the vibration gets worse to the point that my stomach sank. However when I step on the gas everything is fine. While at the station, if I fled it a little higher the vibration stopped. So I decided to get gassed up grab some grub and continue. Made it to Boca around 2:00am. After unloading I disconnected the battery and grounded the terminals to each other and went to bed. Funny thing is, when I picked it up after the fix, the “Service Trailer Brake” light kept dinging about every 30 seconds and lighting up the idiot center. After driving it for a while it went away so I’m operating under assumption that the battery was drained. Which would strangely suggest to me that they didn’t disconnect the battery when they rebuilt the top end.

So I am hoping that this rumble/stumble was a result of something needing to be reset to relearn its new improved parameters. Meanwhile, I ordered a tuner from Black Bear and a catch can. I figured since it’s rebuilt I’m going to work with what I can to prevent any issues all while beginning to put collect up parts to put together a NON AFM setup.

Hope for the best but plan for the worst!!

17 Yukon Denali said:

Well, I replaced the vacuum pump, swapped out the grill shutter……. This morning At 160,000 the dreaded lifter noise. I’m not sure if it’s stuck, collapsed or what. No idiot light, runs rough, sputtered going up the driveway. This one is beyond my abilities so I have an appt in the morning to drop it at the dealer. Alldata shows 9 hrs for 1 side or 11 hours for both so I’ll most likely opt for all 16 to get swapped out. I will keep everyone up to date.

Question….. Does GM have a DOD delete option or am I stuck with these springy turd lifters and an aftermarket DOD delete? If so does anyone know part #s so I info to ask about.

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Dealership service departments will not install aftermarket DOD delete kits, I've asked.

Funny thing… installed the catch can yesterday. Pulled the stupid baterang intake and noticed a shiny new LOMA. I don’t think that they would replace that along with all the other parts. Updated to prevent failure perhaps?

17 Yukon Denali said:

Funny thing… installed the catch can yesterday. Pulled the stupid baterang intake and noticed a shiny new LOMA. I don’t think that they would replace that along with all the other parts. Updated to prevent failure perhaps?

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I believe the procedure is to always replace the Valve Lifter Oil Manifold (VLOM) in the process of replacing the lifters to ensure that the gasket is in good condition and that all of the oil passages are clear and clean.

BlaineBug said:

Dealership service departments will not install aftermarket DOD delete kits, I've asked.

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If only dealer service depts had GM approved Engine Half@$$ delete kits ...

17 Yukon Denali said:

Funny thing… installed the catch can yesterday. Pulled the stupid baterang intake and noticed a shiny new LOMA. I don’t think that they would replace that along with all the other parts. Updated to prevent failure perhaps?

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In TSB when repairing Valve train new vlom with different part number is to be installed.

Which in my mind there is something not right with original vlom and I believe there is a different one installed on repairs done today. You might check your repair order to see if the one they installed on your repair has different part number that TSB I linked.

Blackcar said:

In TSB, when repairing Valve train, new VLOMA with different part number is to be installed.

Which, in my mind, there is something not right with original VLOMA, and I believe there is a different one installed on repairs done today.
You might check your repair order to see if the one they installed on your repair has different part number that TSB I linked.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10209953-0001.pdf

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Even if GM actually bothered to spend money to improve the Variable Lifter Oil Manifold Assembly,
the root problem is still that the 'Off-On' lifters are not as robust / durable / long-term reliable as
their simpler predecessors that are always On.

(Maybe they should have improved on 'Rhoads' lifters instead?)

Couple of reads on Valve train.

So, GM is so cheap, that not only did they not bother to improve / fix the lifter design,
they ALSO:
1. have pushrods that are too weak?
2. are misaligning the pushrods by cocking them at an angle relative to the lifter?
3. possibly both?

Hang on to your GMT400s & GMT800s, y'all ...

Marky Dissod said:

Even if GM actually bothered to spend money to improve the Variable Lifter Oil Manifold Assembly,
the root problem is still that the 'Off-On' lifters are not as robust / durable / long-term reliable as
their simpler predecessors that are always On.

(Maybe they should have improved on 'Rhoads' lifters instead?)

Click to expand...

The non-AFM lifters fail as well. Although typically the AFM lifters fail in a permanently collapsed state, the non-AFM lifters have the roller seize in place and grind the camshaft down as well. They're all crap. Collapsed AFM lifters seem to cause less damage though as in no damage caused to the camshaft typically.