Shops quote $8,000–$12,000 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.
Audi mounted the 4.2 FSI's timing chains at the rear of the block, against the firewall, which means there is no in-car access. When the hydraulic tensioners lose their ability to hold pressure and the plastic guides go brittle and shatter, the only way in is pulling the engine, and on these cars that means the engine and subframe come out together. That's why dealer quotes on this job run into five figures.
The failure itself follows the classic chain-system arc: tensioners bleed down, the chains run slack on cold starts, and the guides, plastic that's spent fifteen-plus years heat-cycling, crack and shed fragments. You hear it as a cold rattle from the rear of the engine, and the ECU flags it with P0017 and P0341 as cam and crank timing drift apart.
What makes this one unforgiving is what happens if you keep driving: a shattered guide or skipped chain on this high-compression V8 is catastrophic, valves into pistons across two banks. At that point the car needs an engine, and good 4.2 FSIs aren't cheap or common. Caught at the rattle stage, it's a big but very doable job: chains, tensioners and guides all replaced while the engine is out, with everything torqued and timed to spec before it goes back in.
If your Audi 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.
Rear Timing Chain & Tensioner Replacement (Engine-Out) 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 $8,000–$12,000 quote. Both are real, both are flat-priced, and both are worth more than a bad yes.
Before you spend $8,000–$12,000, 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 $8,000–$12,000 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 $8,000–$12,000 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: Rear Timing Chain & Tensioner Replacement (Engine-Out) 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.
This is the one chain job where waiting can total the car. The guides don't wear gracefully, they shatter, and when a fragment jams or the chain skips, the 4.2's pistons meet its valves across both banks. Replacement engines for these cars are scarce and expensive, and a B7 S4 or RS4 with a dead engine is worth a fraction of a healthy one. If yours is rattling cold, park it until the chains are done.
If the rest of the car is healthy, usually yes. The B7 S4 and RS4 are appreciating enthusiast cars, and a documented engine-out chain service is a selling point, not a liability. A healthy 4.2 with fresh chains has a lot of life left; a rattling one has a countdown.
Anything that's expensive to reach later, rear main seal, the items buried against the firewall, aged hoses and mounts. We inspect everything that's only accessible with the engine out and quote any add-ons before doing them, so you never pay engine-removal labour twice.
No. Rear Timing Chain & Tensioner Replacement (Engine-Out) 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 $8,000–$12,000 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 $8,000–$12,000 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 $8,000–$12,000. 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