If you cannot get the 300D repaired, I suggest that you look for a 1994-95 E300D. It's the same W124 bodystyle, with the most refinements the W124 bodystyle has to offer, and the often called "flawless" and "bulletproof" OM606 engine, which are stacking up some pretty high miles on them now, with 300K miles not being unheard.
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.