It sounds about right for highway miles, but I agree, it does sound a tad exagerated for in town. He may be a bit slick. Whatever you do, before you buy it, have it checked out by a pro!
The old diesels are simple engines and most who drive them also do the maintenance. All of the power locks work off a vacuum which I understand is much less complicated than electical systems. However, even though I'm learning to do my own maintenance, the power locks, engine shut off,et al, work just fine....Which is not bad for a 25 year old auto.

Before I owned the MB I drove a 1990 Jetta ecodiesel which I also converted to WVO. It got between 40 and 45 MPG. I paid $4000. for it and had 120,000 miles on it. I drove it for 2 1/2 years and sold it for $3700. It was still a creampuff and had 165,000 miles on it. If cared for it'll likely to be in service for another 17 years.
The 1982 MB 300D T gets between 28 to 32 MPG. It had 312,000 miles on it when I bought it for $400.( whichwas just plain lucky! ) But it was soon obvious that it was vastly superior to the VW. It now has over 320,000 miles on it and I fully expect to be driving it and doing most of my own maintenance for many more years.
Butthe Japanese diesels, if you can findone, are every bit as hardy as the German diesels...Andfrankly, I'dtakeJapanesepickup over a VW pickupin a NY minute.

 

That's with newer models, don't worry about it. I haven't had a single issue concerning electric really. Just the overheating issue which wasa bad thermostat..

 

my 81 300d has electrical problems though. the windows are opposite to the switch, when you turn the window up, it goes down, and vice versa. and some of the lights on the dashboard don't work

 

As long as it doesn't leave me stranded or have major mechanical problems I believe it will be cost effective. How many days of downtime a year do you guys average?

 

Down time as in repairs? Not one. (excluding when I bought the car and had to get stateregulation repairs)

 

I had a couple of weeks of down time after I first bought my $400. 1982 300DT.

I did, and had done,a series of preventive measures...Just to be sure,I changed all filters and fluids, including the differential, and had the tranny flushed. Ihad the valves adjusted and the timing chain replaced.I also had all motor mounts, motor shocks, tranny and differential mounts, as well as sub frame mounts andflex discsreplaced. I bought new tires and shocks, put on new calipers, and a rebuilt steering gear.

I then took the injectors apart, cleaned them and installed new nozzles, return lines and of course, new heat shields. Next I serviced the ALDA by cleaning the banjo nuton the manifoldthen by passed the switchover valve, and installed a bb in the vacuum line that goes into the EGR valve.

I could have not done any of the above and maybe driven it for years without any trouble. But since I intend to drive it for many years to come while driving for free on WVO, I wanted it to be running as perfectly as possible.
I then installed a http://www.greaseon.com kit and it now burns WVO which I collect from 2 Japanese restaurants.

 

I have a 1983 240d. It gets about 28-31 mpg depending how fast I go. I will sell this one for $3800 if you want to know more email me.

sweetstick@rogers.com

 

I have a 1985 190D auto. I get about low 30's mpg. I can't wait to get some non-winterized diesel and see what she can do. I have been told that the anti-gel agent they use in the winter robs a few mpg's. I'm actually selling mine now to upgrade to an E or S class diesel. The mpg's are great, but I need a little more room. The car is the most reliable in my fleet and it's the oldest too!

 

I'd guess the 190D gets the best mileage.... as if you didn't know~ How many mile does it have, and how much are you asking?