Some mid-2000s Mercedes M272 V6 engines wear out the balance shaft gear. Codes, which cars, what the repair involves and what owners paid.
The M272 is the 3.0 and 3.5 V6 in a lot of mid-2000s Mercedes (C, E, CLK, ML, R, SLK and others). A chunk of the earlier engines had a balance shaft gear that wears down, which messes up cam timing.
How it shows up
- Check engine light, usually cam/crank position correlation codes
- Sometimes a slightly rough idle or nothing you can feel at all
- Eventually, if ignored, worse running and timing problems
Plenty of owners drive around with the light on for a while because the car seems fine. The wear doesn't fix itself though.
Is my engine affected?
It depends on the engine serial number, not just the model year. Mercedes updated the part, and later engines are generally fine. A shop that works on Mercedes regularly can check your engine number for you, and it's worth doing before you buy one of these used.
What the fix involves
This is a big job. The front of the engine comes apart, and on many cars the engine comes out. The balance shaft (and often the timing chain, guides and sprockets) gets replaced. Lots of labor, which is why all of our reports are in the thousands.
Our data, and a weird detail
Three reports, all from 2015. The lowest was actually a dealer, but that owner got help from the service director, which is basically goodwill. Without that, dealer pricing on this job tends to be higher. The Mercedes-only indie report was the highest of the three. So on this one, it's worth calling Mercedes and asking about goodwill even on an older car, especially if you have service records.
Ask
- Did they confirm the engine serial range?
- Is the timing chain being replaced too?
- Is the engine coming out, and what else are they resealing while it's out?