Eaton acknowledges that the useful service life of the M62 supercharger is 100,000 to 125,000 miles. Will the M62 last beyond that? I'm sure that many will, but I'm also sure that some will not.
In the automotive world generally, 125K mile service life is pretty good. I don't know too many "domestic makes" customers that expect their car to last much longer than that.
However, we Mercedes folks look at things a tad different. We exclaim "ONLY 125,000 miles?"
Now, is there a way of increasing the service life? I had some experience with an Eaton unit on my Dad's Thunderbird SC years back. At that time, the Eaton unit basically quit at about 120,000 miles. Since a few years old T-Bird was a $3000 used car ($30K new!) there was no reason to spend the cash to put a new unit on it. This might not be true of a Mercedes, even a C-Class. The thing we did learn was that the Eaton units were not designed to be serviced along the way, and I talked to SC owners that had tried, and had not extended the service life a bit.
The M62 might be different, but I doubt it. Now, with so many of those M62 equipped cars out there, if there comes a time when lots of them are wearing out, Mercedes will probably be rebuilding them, and they'll be available at about half the price of the new unit. On a cost-per-mile basis, that makes it a bit better.
If you study the mechanics of the blower and the incredibly tight machining clearances, you can see why it's quite something that these guys last as long as they do.
1998 C230 "Black Betty"