Shops quote $4,500–$7,000 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.
The M156's second famous weakness lives in the valvetrain. Around 160,000 km, the intake camshaft lobes begin to wear, the hardened surface breaks down, the lifters that ride on them get chewed up, and the camshaft adjusters (the variable timing units on the end of each cam) follow soon after. It's a chain reaction: once lobe wear starts, every part in contact suffers.
You hear it before the computer sees it: a tick from the top of the engine on cold start, gradually present at all temperatures. As the adjusters lose their ability to hold commanded timing, the idle gets rough and codes like P0010 and P0020, camshaft actuator faults, appear, often with a noticeable loss of the engine's trademark punch. Plenty of owners get quoted sensors or solenoids first; on a high-mileage M156, the smart move is a visual inspection of the lobes through the valve covers before spending anything.
Ignored, worn lobes shed hardened metal into the oil, which circulates through the entire engine, bearings, oil pump, the works. A valvetrain repair caught early stays a valvetrain repair. Driven for another year, it can take the bottom end with it.
If your Mercedes-Benz 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.
Camshaft Adjuster & Lifter Replacement (Cam Wear Repair) 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–$7,000 quote. Both are real, both are flat-priced, and both are worth more than a bad yes.
Before you spend $4,500–$7,000, 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–$7,000 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–$7,000 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: Camshaft Adjuster & Lifter Replacement (Cam Wear Repair) 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.
Cam lobe wear is self-accelerating: every rotation grinds hardened debris into the oil, and that debris wears bearings, lifters, and the oil pump. The difference between catching this at the ticking stage versus a year later is the difference between a top-end repair and an engine rebuild. The tick is the engine telling you now.
Depends entirely on the lobes. Caught early, the cams survive and you're into adjusters and lifters. Caught late, one or both intake cams are scored past reuse. That's exactly why we inspect before quoting, the difference matters, and guessing in either direction costs you money.
No. Once the lobe surface has broken down, the wear is mechanical and irreversible, oil changes slow the collateral damage but nothing reverses it. Fresh oil is part of the repair, not a substitute for it.
No. Camshaft Adjuster & Lifter Replacement (Cam Wear Repair) 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–$7,000 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–$7,000 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–$7,000. 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