Shops quote $4,000–$9,000 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.
BMW's N20 four-cylinder turbo went into nearly everything from 2012 to 2017, 320i, 328i, X1, X3, 428i, and it carries one of the best-documented defects of the modern BMW era. The timing chain rides on plastic guide rails, and on the N20 that plastic turns brittle with heat cycles. The guides crack, shed fragments into the oil pan, and the chain starts flogging around with slack the tensioner can't take up. It's serious enough that it became the subject of class-action litigation.
The noise you hear on a cold start is the tell. Oil pressure hasn't reached the tensioner yet, so for a few seconds the stretched chain rattles against broken guides before quieting down. As the wear progresses, cam-to-crank timing drifts and the DME logs correlation faults. P0016, P0017, and timing-chain code P0008, usually paired with a rough idle. On the N20 the chain lives at the back of the engine, against the firewall, which is exactly why shops quote so many hours for this job.
If a worn chain jumps teeth, the pistons meet the valves. At that point you're not buying a timing chain anymore, you're buying a cylinder head rebuild or a replacement engine. Every N20 that rattles on cold start is on that countdown, and there's no way to know how many heat cycles are left on the guides.
If your BMW 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.
Timing Chain, Guides, Tensioner & Valve Cover 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 $4,000–$9,000 quote. Both are real, both are flat-priced, and both are worth more than a bad yes.
Before you spend $4,000–$9,000, 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 $4,000–$9,000 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 $4,000–$9,000 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: Timing Chain, Guides, Tensioner & Valve Cover 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 stretched chain on cracked guides has exactly one failure mode left: it jumps. When that happens on an interference engine like the N20, valves contact pistons and the repair goes from a one-day chain job to a head rebuild or replacement engine. The rattle never fixes itself, guide plastic doesn't grow back, and the cost difference between doing it now and doing it after the jump is the difference between a repair and a write-off on a lot of these cars.
Three signs together make it conclusive: the rattle is loudest in the first seconds of a cold start, the codes are P0016/P0017/P0008 (cam-crank correlation), and on inspection the cam timing is off when checked against locking tools. We confirm all of that before recommending the job, if your noise turns out to be something cheaper, that's what we'll tell you.
No. Timing Chain, Guides, Tensioner & Valve Cover 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 $4,000–$9,000 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 $4,000–$9,000 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 $4,000–$9,000. 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