It calls into question your own knowledge and experience with turbodiesels. Is this your first foray into MB Diesels or are you an old hand?

Did you check the line from the manifold to the switchover valve to the ALDA? Don't tip your hand too soon. You could turn the tables on him if he's pulling the wool over your eyes and have a fine running TD for a song and a few minutes of cleaning.

A rule of thumb for an 81 TD is 17 seconds 0-60 mph time. Probably best done with the seller behind the wheel and you timing. If it's closer to 20 seconds, take everything else he says with a grain of salt.

Sixto
95 S420
87 300SDL