The 2005–2008 M273 V8 shares the same weak idler gear as its V6 sibling — and it strips the same way. We do the full gear-and-chain repair at your home, with the right tooling to keep the engine in the car.
The M273 V8 in the 2005–2008 E500, ML500, S500, and CL500 uses the same failure-prone idler gear design as the M272 V6. The gear's teeth are made of a material that simply wasn't up to the job, and they wear away with mileage. As the teeth strip, the timing relationship between the crank and cams drifts, and the computer starts logging P0016 and P0017 — crankshaft-to-camshaft correlation faults.
Owners usually notice it as a vibration at idle that wasn't there before, sometimes with a rattle from the front of the engine. The codes are the giveaway: P0016/P0017 on an M273 of this vintage almost always traces back to the worn gear, not the sensors that less experienced shops keep replacing. Chasing sensors on this engine wastes money on a problem that's purely mechanical.
The repair is famous for being quoted as an engine-out job — which is where the most extreme estimates come from. With the right Mercedes-specific tooling, it can be done with the engine in the car. Either way, waiting isn't an option forever: a chain that jumps on this interference V8 puts valves into pistons, and the repair bill multiplies.
If your Mercedes-Benz is doing any of these, this is the likely cause:
P0016/P0017 on this engine is the warning shot. The gear doesn't heal, and every drive grinds more teeth off it. The failure mode — a jumped chain on an interference V8 — means bent valves and a torn-down top end at minimum. Fixing it while it's still a gear-and-chain job is dramatically cheaper than fixing it after.
With the correct Mercedes timing and support tooling, this job can be done with the engine in the car — which is exactly how we do it in your driveway. It's a two-day setup with the car staying put overnight. The engine-out quotes you've seen are one way to do it, not the only way.
Because it's one of the biggest labour jobs on this engine, and many shops quote it as an engine removal. Big hours at big GTA shop rates add up fast. We quote you one flat price for the complete repair — gear, chain, tensioner, guides — before we touch a bolt, so the number you agree to is the number you pay.
On a 2005–2008 M273 with idle vibration, almost never. Those codes report a real mechanical disagreement between crank and cam position, which is exactly what a stripped idler gear causes. We verify before repairing — a scan and inspection at your home tells us for sure — but throwing sensors at this engine is the classic wasted-money move.
No — the updated part corrects the original material problem. Combined with a fresh chain, tensioner, and guides, the repaired engine is more robust in this area than it left the factory. This is a fix-it-once job.
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