Buy only a turbodiesel; the non-turbo car is under powered.
Avoid cars with rust.
Try to buy a car that's for sale by its owner, not some car that's being
SOLD to you. Find the car in your local newspaper or Autotrader.com. Be
patient for the right car, buying a M-B is elective, so take your time.
Car's condition and maintenance records prevail over pure mileage on the
The 5 cylinder diesel is a tough old engine; change its oil and filter
every 5K miles, adjust its valves, yes these are mechanical and need to
be adjusted, every 15 K miles, replace the air, fuel and transmission
oil & filter every 30K miles. A reasonably well maintained engine is
good for 250K miles, some, with extra maintenance, reach 400K miles.
Unless you really need a wagon, the 4 door sedan is a great package and
the somewhat larger 300SD is a relative bargain and, it uses the same
engine and transmission.
The wagon has a rear suspension with a hydro pneumatic self leveling
feature. Its powered by an engine driven hydraulic pump on the cylinder
head. These systems can be expensive to have fixed, particularly if the
owner is ignorant of its workings. Some shops want to replace, replace,
replace; you need to understand what's needed and why to keep the cost
Finally, don't take such an old car to a dealer, find an independent M-B
shop and take it to them or learn to DIY. These are simple cars that
lend themselves to DIY maintenance and most repairs. As part of its
purchase have a M-B shop undertake a prepurchase inspection, including a
compression check of the engine. Its $$ well spent to know that (i) you
found a decent car or (ii) avoided a money pit.