How long will a Mercedes diesel engine last?
Depends on maintenance. With the use of cheap, non-diesel rated
oils and irregular oil changes 200,000 miles would be about all you
could hope for. With proper maintenance, good oils like Shell
Rotella T, or Amsoil synthetic, gentle driving, and a few add-ons
like a good bypass filter and fuel water separator, 400,000 would
be expected and 500,000 not unlikely.