Car had obviously been neglected by the previous owner. I'm sure these cars would outlast almost anything else with proper maintenance. With my particular car I needed to replace a front wheel bearing, starter, and thermostat within a short time after purchasing it.
The automatic climate control system is a lost cause on these cars. If it works at all be glad. Mine won't do anything other than upper vents and defrost. The lower heating vents won't open when selected. I get by okay with this. The air conditioning needs recharging, but I won't bother because here in Vancouver, British Columbia there is no need for it. We get two months of semi-nice weather, 2 weeks of 30 degree weather, and 10 months of dreary, rainy, depressing, cold hell. Why do I live here?!! Anyway, test the climate control system fully, and knock $1000 off the price of the car if there's anything wrong. Even that probably wouldn't cover repairs if you get the dealer to do it.
My sunroof doesn't work, and I haven't bothered to figure out why yet...
Working on the car can be a real pain. I am a college trained mechanic and have worked on many cars. I have to say this one is the worst pain in the ass to work on that I've ever seen. It took me 3.5 hours to change the thermostat because it is located in an awkward position beside the turbocharger. I was cut to ribbons up to my elbows and placed an ad in the paper to sell the car after performing this task. I had a change of heart after a few days and didn't sell the car. Changing the starter wasn't much fun either. I had to disconnect the drag link from the steering arm to get the starter out!!! What a pain. I also had to replace an expansion joint in the exhaust manifold between number 2 and 3 exhaust ports. That wasn't any fun as it requires removal of the exhaust manifold, along with the charge-air ducting. With a few slight design modifications many of these tasks could have been made much easier. Perhaps later models are better... I'll find out one day.
As a matter of routine maintenance I have replaced the glow plugs, diesel injectors, and coolant. I change the oil every 5000km, but recently I have switched to Mobil Delvac 1 synthetic which I should be able to leave in for much longer.
Previously I drove a 1985 BMW 323i which obviously performed slightly better, and was a little more nimble.
For approximately 6 months I owned a Kawasaki ZX-7R sport bike. It was so fast that it completely ruined my car driving experience. All of a sudden the BMW seemed so incredibly slow, that there was no thrill left in driving it at all! However, I didn't want to get killed on a sport bike, as I eventually would, along with everyone else who rides them. This lead me to purchase a safe, slow tank: The Mercedes 300d Turbo. It is fairly fast for a diesel car, but in the grand scheme of things it is a slug. This is fine with me, as everything else also seems slow after having ridden the sport bike.
Maybe I'm just getting old or something, but I find this big diesel tank with automatic transmission quite pleasant and relaxing to drive.
The engineering is good, from a quality standpoint.
I find that I use about 8 litres per 100 km, which is excellent mileage for a car of this size and weight.
Now that I've worked the bugs out of it, and corrected the problems which were due to the previous owner's neglect, I'm sure I could drive this car for 20 years with regular maintenance.
Parts are fairly easy to find, and priced resonably considering their excellent quality.
I only gave it a 6/10 for operating costs because in order to maintain the vehicle properly you do need to spend a bit of money, and there are no parts for $3 at your local Wal-Mart...so generally higher maintenance costs than a run of the mill domestic car. Heck, I could have bought a brand new domestic car for less money than this 15 year old machine, but this will probably still outlast one of those...
I would recommend it overall, but don't buy one that is priced lower than expected!!! You will end up spending more to repair problems than if you just bought a good one for a higher price to begin with. If you work on it yourself like me, then this might not be such a concern. Just be aware that a good deal will soon turn bad once problems start to surface...