If it is AFM equiped and actually has a Collapsed/stuck AFM lifter. That is a direct injection engine though so it has a lot of extra things to consider beyond just the lifter. The Direct injection engines after 2014 are prone to other issues such as: -Bent pushrod from factory interference with hole in head and/or spring on AFM lifter, or internal lifter failure/blowout that caused it to bind/wedge. (This has the same symptom as a collapsed lifter in many cases) -Chewed up cam lobe and lifter roller. This is caused by the soft metal the newer cam is made of and I recommend a full AFM delete at this point. The symptom from this is a light ticking in most cases. -Collapsed AFM lifter. This happens on the direct injection engines usually because the VLOM is leaking pressure into the oil towers when it shouldn't. The VLOM mod I do it pretty much needed on these models. I have a video exclusive just for this VLOM unit kzfaq.info/get/bejne/rN2UfLF22N-9fGg.html -Broken timing chain tensioner. Not that common but worth a mention One last thing to note is on DFM. In 2019-2021 they started to implement a system called DFM. The DFM or Direct Fuel Management controls all 8 cylinders instead of only 4 like AFM does. This system to my knowledge wont allow my products to work with it. It has 8 separate solenoids bolted into the block instead of 4 solenoids in a VLOM assembly. It still functions the same but with twice the AFM lifters. It's still unclear as to the reliability of these but I do know they still bend pushrods occasionally. If anyone reads this within driving range of southern South Dakota with one needing service, I would love to crack it open and will give a discount to the first one I get a chance to work on.

keep clean oil in your car & it will not happen

So mine has the tick but no check engine light at all runs perfectly?

@@19shawnshawn89 same

@@jgruen9854 mine ended up being the dod faling and my lifter made my cam dinner

#4 me too a week ago, did you have a code for #4 ?

These comments make my day. Thank you for taking the time to stop by and leave this comment It means a lot. I really need to get back to posting more videos.

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What you did wrong was not turning off the system. If you haven't turned it off yet, you should. These systems once failed tend to fail again within the first year or two after lifter replacement.

@@CrazedPerformanceRepair oh damn I didn't ad that part . I did send my ecu off to a reputable speed shop and had the did flashed out. So it is full time 8

Okay, if you did have it done then you must be right and it is just because you didn't pull the rocker off.

Yo Brother I hope you have figured out out your issue!

Bummer hopefully it's not a spun lifter because of a bad plastic guide. Pop the cover off and use the starter to crank it over while watching rocker. If it works at first then stops it may be spun. This is the worst case scenario for you. Something you can't anticipate or prevent while having AFM lifters. When it happens it wipes out the camshaft.

@@CrazedPerformanceRepair I’ll do that. Thnx for resp! This morn started, after warm up idle down, 600 rpm. Slight mis in P, shift to D, feel mis a little more, waiting for cel to flash w it’s brother stabilitrak…not happening but idle poor, hit a/c (to load engine) now you can feel mis…then she starts a shak’in good but at that exact moment live data showed FP go from 43 to 57 lbs and STFT 0.0 and LTFT go to -0.08. These are now normal values right? I have noticed in past when that mis gets bad, FP has gone from 43 to +55 lbs . Got P304 during that heavy mis.. put in P, killed a/c and smoothed to just poor idle. Odd that FP rise to normal causes mis to exaggerate.

@@ericmausolf8682 I think the fuel pressure is irrelevant. It's likely more related to open vs closed loop. The stft might sow close to 0 but I bet the ltft is way off being 1cyl worth of extra fuel is being added to other cylinders while using less air. You probably shouldn't be driving it like that though. There is a puddle of fuel sitting behind the intake valve that's not opening. If it leaks into that cylinder after shutdown at the bottom of compression stroke, you could be risking a hydrolock condition.

Does it only do it when cold?

I'm in process of moving my shop to SE corner of South Dakota. So if you are with in driving distance of that area you will be able to bring the vehicle to me for service.

You might want to see my leaking exhaust manifold video. This vehicle ticked all the time.

@@CrazedPerformanceRepair thank you for the reply. do you have a option where I could pay you to listen to a short video and get your logical opinion ?

Plugged oil filter, Badly leaky lifter, or second camshaft bearing.

You prob have to pull the head. The valve might be sunk in the head or something. Check valve stem height and compare it to the others. If it's sitting higher then the rest it has sunken in or worn out.

@@CrazedPerformanceRepair wasn't the valve. Took the head back off and replaced the other lifter in that cylinder and boom ran great. Idk what was going on because that lifter looked fine. The other one was visibly collapsed. But I guess both were bad.

@@TheTechGuider interesting, I've heard of only a couple do that. It happens but isn't very common.

You might have a manifold leak and a lifter failure. Check to see all manifold bolts are in place. Then check compression. You could have a spun or stuck lifter but see my long video for diagnosis.

Attempt to seat the lifter, than put the rocker on and turn the engine over by hand. If the rocker works the lifter has been released. If it was released don't forget to use the starter relay to double check that it says. Make sure the VLOM is bolted down when you do this.

@@CrazedPerformanceRepair could you please advise if one litre of Dextron 6 Transmission fluid be used along with 4.5 litre of 5w30 in GMC YUKON 2013 for a full cycle of 3000 miles ?

Message me on my site.

Yes, I run my own gig from home. I recently moved and am building a bigger shop now.

It’s called a needle scaler ( with the scales off )

Cylinder number 8 is not a AFM cylinder. It can't fail the same way the AFM lifters fail. The AFM lifters failing comes down to oil pressure at the lifter during activation. If the oil pressure is below 26 PSI at the lifter when it activates the locks will bind. This causes internal damage on the AFM side of the lifter thus leading to the lifter locking up when it activates. That's where my lifter trick comes in. Doing it freeze up the lifter and turning off the system keeps it from happening again. You need to make sure that it applies to you and your situation though. There is more than one way the lifter can fail and that is only one of the ways. If you have a floppy loose rocker you most likely have the scenario I use the tool for.

@@CrazedPerformanceRepair Thanks for all the info, I removed the cylinder head again and replaced both #6 lifters. Happy to report engine runs fine now. learned a lot from your videos, thanks again!

That is good practice every so often but I would not do it at every oil change. I would also get the system turned off on the vehicles you purchased before attempting any type of flush.

@@CrazedPerformanceRepair do you have a shop open

@@justinlandis5672 Not at the moment, I am trying to get situated to move to SD. I do have a list of shops that claim willing to do AFM repairs listed on my website though.

Visit my website www.crazedperformancerepair.com and send me a message there.

Just disable the system electronically first. A great source for this is LT1swap.com

It's technically incorrect to call it a collapsed lifter. It's technically a failed AFM portion of the lifter and has nothing to do with the normal hydraulic side of it. Unfortunately if I word and label things that way the video would never reach anyone. What happens is the AFM locking paws on the inside AFM portion of the lifter damage the shelf on the outside portion. Then when the lifter activates it's AFM the inside portion gets stuck to the outside portion because of the knurling effect that the damage caused.

That’s the throttle body position sensor. Or it was in mine anyways. It was replaced for free because I was under 110,000 miles. You probably figured out by now

Do the VLOM mod and the PCM reprogram. Otherwise from what I've read, there is a high likelihood of reoccurrence.

Yes it could be, all depends on what has failed and how.

Lt1swap.com hptuners has gotten way too expensive.

This procedure won't help on the non AFM cylinders. Check the basics first.

No because it is sorta a myth. They fail because of lack of oil pressure during AFM activation which sometimes is caused by sludge. Issue is when they stick it's not sludge holding them, it's damaged metal area inside the lifter it's self for the AFM portion of it. See my long video to see the part that gets damaged.

The oil pressure issue could be several things, Since it is a 2008 the oil sump o-ring could be just starting to leak from age causing it to flatten out the seal. If it is just under 40 psi at hot idle its not that bad yet, but if it is around 30psi hot idle the I would want to address it.

@@CrazedPerformanceRepair thank you for gettng back to me. Yes it's dropping pretty low. Am wondering if the pump itself might be going out. This truck had several bolts loose inside or I guess around the heads something like that And was pour oil everywhere, we got them all tightened and did the other work but I can't help but wonder with all the leaks and issues if maybe the pump had to work over time and might be wearing out or do they just basically die. Sorry I'm not very well versed as I'm the wife & can do some work on cars but the husband did the major work and he keeps saying he can't figure out why the pressures so low. We still owe $15000 on it and are worried about it dying. It started leaking right after we bought it. We did a first oil change & it basically looked like it blew up, oil everywhere. It doesn't appear to be leaking anymore but the pressures usually dropping much lower than it should. I think the dealer put that stop leak crap in it. Could that mess up ther pump. We changed sensors and the little filter under it too. All new oil & filters. Afraid we're going to be paying on a five year loan for dead vehicle.

You might just have a bad oil pump o-ring. It is very rare for these pumps to actually fail. I should be releasing a timing chain video this weekend that shows how to remove the oil pan and pump. If I release that video this weekend you can use it as a guide to pull your pan and replace the oil sump o-ring. It is a cheep o-ring, a oil pan gasket and a oil change worth of expense, so it is not to much money to do. It is also a very common problem and worth doing anyway if you have the skill and time to do it.

@@CrazedPerformanceRepair ok , yes sounds like a good idea . We can wait to do oil change after you put your video out he's laid off so will have time to tinker. We'll try you'r suggesting can't hurt & fairly cheap because I think the pumps working but something's just not right with the pressure. I almost wondered if they put so much of that stop leak in it that it's clogged the pump and affecting how it works. Right after that first oil change that poor truck had so much oil pouring out of it that it looked like someone just dumped oil all around the engine. It had several valley cover bolts loose too. We think the dealer cleaned it then dumped buckets of stop leak in it & sold it to us. It had very low mileage probably because the original owner had to constantly put it in the shop & couldn't figure out where the leaks were coming from so it sat until he could sell it or fight with gm as a lemon, my guess. Anyway we tightened the bolts & changed the DOD to a straight 8 that worked like a charm but it's still having the odd pressure readings. Like you said could be a number of things. Thank you so much for your help & getting back to me , we'll keep an eye out for your new videos as they've been extremely helpful. We'll get the parts this week & be ready to go after your video comes out. Know it'll be a while for you to post that gives us time to finish up our car 😉 good timing was meant to be. Take care stay safe & again thank you for your help & videos.

I have not done one myself but did have a customer say that is works. He even told me the VLOM plug fit.

Try to just to spray some transmission fluid down in the air intake when it's running if it's a collapsed lifter it will stop making a noise almost immediately if it doesn't then then the lifter is messed up real bad you had to replace

Is it cylinder 7? If so probably a pcv valve cover issue putting oil in your intake. I have a video on that as well.

That sounds more like a spun rod. Except the misfire part of it hmmm... You should pull the valve cover anyway and check for a loose rocker just in case.

Vehicle only has 61k km (38k miles) which makes it even worse, didn’t really expect an engine problem this early

Sorry to hear about your truck . I’m having the same problems with my 2018 Sierra . Did you find the issue ?

Wet with oil or fuel. Might be best to PM me on my actual website btw

Why not just use LT1swap.com? It's only $50 and some shipping.

Yes I have had a few but they have all had very loose VLOM bolts. The vast majority of failures are on dirty engines.

@@CrazedPerformanceRepair do you think this dirty engines is a causal factor in sticking or just coincidental, the mechanical concept by design is ok but use of incorrect oil and oil change intervals the real culprits?, as curious for reason we have such engines in Australia but not to any where near volume in US but must say our oil change culture is very rigorous so wondering on wether we should be deleting fiction also?

Dirty engines do play a factor if the contamination causes a drop in oil pressure to the lifters. The other huge factor is general wear and tear. As these engines age the clearances get bigger and the volume of the pump can not longer keep up to maintain above 30 psi in all conditions. The system fails when the locks can't be activated fast enough. I would turn off any system that had over 100,000 mi or 160,000 km but if it was my own vehicle I would shut it off as soon as warranty was up.

I changed the oil to a higher viscosity after popping the lifter... everything seems fine so far. My 07 Tahoe has 250k miles on it and I am guessing like you said larger clearances need higher viscosity... but then again you lose some engine power along the way due to higher friction. These engines are very expensive where I live. Will cost me around $10k to get a new one. Might as well change the entire car.

put fully synthetic oil in and change it every 3 to 4 k helps alot

I picked up an LS engine with that same problem ( tick but no collapsed lifter). The tick was from metal that wore away on the lifter roller and chewed up the cam lobe.

I’m interested in a answer

I'm located in South Dakota by Nebraska boarder.

No, but usually. It does always have a floppy rocker if it's collapsed. You could have a spun lifter too.