I'm wanting to buy a 300Turbo Diesel Station Wagon....the early eighties 5 cyl model 123, and I thought I might ask for suggestions as some ways to best proceed.It would be my first Mercedes; e.g.Anyone know of one for sale or a good place to look? Is there a certain year to avoid? Are Turbo Diesels difficult or expensive to maintain? What would it cost to rebuild the motor? ..etc..etc.. Any thoughts on this subject will be greatly appreciated!
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 odometer.
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 in check.
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.
Blow-by seems greater on a diesel than most gas engines and is NOT an issue.
Being a compression engine the true test of a diesel's condition is a compression check. If the engine is in good condition its compression will be within specifications and if it's worn that will show in lower than specified compression. These engines have a 21.5:1 compression ratio; its compression specification is 320 to 350 psi with 45 psi maximum variance between cylinders and 220 psi being the lowest acceptable compression (at which point it will start with difficulty).
This sounds like the perfect car in the sense of its total use, documented maintenance history and overall appearance. This is the kind to buy - after a pre-purchase inspection which will confirm its good condition and put your mind at ease as to how much life remains in this car - or gives you good reason not to buy it or negotiate a better price to cover some work that's imminent. If the seller believes in his car there should be no objection to a professional inspection at your expense.
So, what are you waiting for?
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