Shops quote $4,500–$8,500 for this one, and the quote usually isn't the ripoff, the job really is that big. Here's what's actually failing, what the correct repair involves, and the honest part: this is not a job I do in a driveway.
GM's 5.3L V8 (L83 and L84) in 2014–2023 trucks and SUVs uses Active Fuel Management, later Dynamic Fuel Management, to shut down cylinders at cruise. The deactivation lifters that make this work have an internal locking pin that collapses the lifter body when a cylinder is switched off. Over time, that locking mechanism wears or sticks, the lifter collapses when it shouldn't, and the roller stops following the cam lobe properly. Cylinder 6 is the most common victim, and that loud mechanical tick or knock at idle is the collapsed lifter hammering against the cam.
Once a lifter collapses, the camshaft lobe under it starts getting wiped, the roller skids instead of rolls, grinding the hardened lobe surface down and sending metal through the oil system. That's why this job is almost never just a lifter swap: by the time the noise is obvious, the cam usually shows wear. The misfire codes that come with it (P0300 through P0306) tell you which cylinder is dropping out, and oil consumption tends to climb alongside it because the same trucks burn oil through the AFM system's pressure-relief venting.
The fix is to pull the intake, valley cover and both valve covers, get the heads' rocker gear out of the way, extract every lifter, and replace the camshaft if the lobes are damaged, which on a truck that's been ticking for weeks, they usually are. Doing all 16 lifters at once is the only repair that makes sense; replacing one and leaving 15 aging originals in place is how this job gets done twice.
If your GM is doing any of these, this is the likely cause:
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See how that range compares across Mississauga, Oakville, Milton, Brampton and Etobicoke in the GTA Repair Price Index, honest shop & dealer ranges for the jobs people actually get done.
AFM/DFM Lifter & Camshaft Replacement is on my published list of jobs I turn down. It needs a hoist, a press or a machine shop, and I work out of driveways with hand tools. That list is public on my trust page. I'd rather lose the job than learn it on your engine, and you should be suspicious of anyone who says yes to this over the phone.
So here's what I can genuinely do for you, holding a $4,500–$8,500 quote. Both are real, both are flat-priced, and both are worth more than a bad yes.
Before you spend $4,500–$8,500, have someone independent confirm that's actually what's wrong. This is a diagnosis, not the repair, no hoist, no lift, nothing comes apart. I scan it, test it, look at it with you, and tell you straight whether their diagnosis holds up. If it does, I say so and you go pay them with confidence.
Book the second opinion →At $4,500–$8,500 on a car that might be worth not much more, plenty of people replace instead of repair, that's a completely reasonable call. If that's where you're heading, get the next car measured before you hand over money: 150 published points, at the seller's location, written report the same day.
Book a pre-purchase inspection →Tell me what you've been quoted and what the car is doing. $100–$250 flat, at your location, and you get a straight answer either way.
Rather just have the quote read? The free quote check tells you whether the number is in line, no visit needed.
Jobs on this car that ARE mine:
Not so you can do it yourself, so you can tell whether the shop quoting you understands the job:
That's the job. It's why this one belongs on a hoist instead of in a driveway, and it's why $4,500–$8,500 usually isn't a ripoff, it's a big repair honestly priced. What's worth checking is whether that's really what your car needs.
Get the diagnosis confirmed firstPlain version: AFM/DFM Lifter & Camshaft Replacement needs equipment a driveway doesn't have, a hoist to get under it properly, a press or a machine shop for the parts that come out, and a controlled space for an engine or gearbox that's in pieces for days. I work out of driveways with hand tools. That's not false modesty, it's the published limit of what I take on, and it's listed on my trust page alongside the warranty.
What that means for you: this page is here to tell you what's failing and what it should cost, so you walk into a shop knowing the job instead of nodding at a number. And if you want that number checked before you pay it, that part I can do, $100–$250 flat, at your location.
A collapsed lifter doesn't stabilize, every cold start grinds more material off the cam lobe and pumps more metal through your oil system. Caught early, it's a lifter-and-cam job. Ignored for months, the metal debris takes out bearings and the conversation changes from a repair to a replacement engine. The tick is the cheap stage of this failure.
All 16, every time. The lifters are the same age and the same design, if one collapsed, the rest are on the same clock, and most of the labour is getting to them. Doing one lifter now and another in 20,000 km means paying for this job twice.
The replacement parts are an updated design, and a strict oil-change interval with the right oil dramatically extends their life. Some owners also choose to disable AFM electronically or convert to non-AFM parts while everything is apart, we'll walk you through the options before we start.
No. AFM/DFM Lifter & Camshaft Replacement is on my published list of jobs I turn down, it needs a hoist, a press or a machine shop, and I work out of driveways with hand tools. I'd rather lose the job than learn it on your engine.
Two things, and both are real. A second-opinion diagnostic at your car, $100–$250 flat, at your location, so somebody independent confirms that's actually what's wrong before you commit to a $4,500–$8,500 repair. And if you're weighing replacing the car instead of fixing it, a pre-purchase inspection on the replacement, $149–$399 flat, at the seller's location.
Because the useful part isn't the wrench. It's knowing what's actually failing, what the correct repair involves, and that shops quote $4,500–$8,500 for it, so you walk in knowing the job instead of nodding at a number. If you want that number checked before you pay it, that part I can do.
Send it over for a free second opinion. I'll tell you straight what the job actually involves, and if their quote is fair, I'll tell you that too.
Get a Free Second OpinionOther makes:
I'm not the guy who does this repair. I'm the guy who tells you whether you actually need it, before you spend $4,500–$8,500. Second opinion at your car, $100–$250 flat, in Mississauga, Oakville, Milton, Brampton and Etobicoke.
Book a Second Opinion Inspect a Replacement CarYour options on this one