I looked at an 84 diesel before buying my 560SEL. You could really smell fumes when you stopped at a light. Is this common? I'm thinking of picking a diesel as a second MB and wondered if I need to check for this when test driving.
Thanks

One thing that can cause this is excessive blowby. The engine will vent an excess of combustion fumes into the air cleaner housing. If the engine is old and tired, it can vent so much exhaust that it will come out of the air cleaner housing. The ventilation system will intake this air and blow it into the interior. I'm sure that other possibilities exist, but this could be the culprit.