I am the prospective buyer of a 1984 240D wagon with 137,000 miles. I've been interrogating the seller with questions gleaned from Google search results for the D24 motor, as well as questions here:

http://www.swedishbricks.net/faq/engdiesel.html

The owner reports that in 5000 miles the engine has not burned any oil. More specifically, he hasn't had to add any.

Is this a big red flag?

Thanks!

 

ABSOLUTELY NOT!!

If they are changing the oil at regular intervals, even with that many miles you will never need to add oil.
I am a big VW diesel geek and mine has over 350k miles on it and if I change my oil every 6k miles I don't have to add any.