Mercedes 300d reliability
Trans was going when I bought it... lasted 2 years (and god knows how many prior to that) before finally losing 1st gear (mostly). If I idled it, it would move 1-2 mph, & reverse still worked, so at least I could move the car.
When I set out to purchase summer and winter vehicles, I did extensive research, which ultimately led me to arguably the most dependable American 4x4 (XJ Jeep Cherokee) and one of the most reliable cars ever built, the Mercedes 300D.
After changing out both fuel filters, cleaning the banjo bolt, and a couple of diesel purges, this baby runs like a champ! People who say these are slow must have been running clogged fuel filters or a tired turbo. While this car is by no means fast, but if I tromp the throttle, it scoots well for a heavy car with not a lot of HP.
Cannot imagine the non-turbo 300Ds (late 70s early 80s), 125 HP isn't great, but 80 HP would be downright scary!!
Excellent build quality. Iron block + iron head = 0 gasket issues & reliability. One of the very short list of vehicles that can withstand the brutal roads in Africa (and Michigan) and not fall apart. That really speaks volumes. Diesel is slow to warm up when it's cold, but it has excellent heat when it finally does. I have a great deal of fun when people ride my ass while driving... I hit the pedal and blow some smoke at them like a James Bond smoke screen! They usually drop WAY back or pass me, but any tailgating issue is quickly resolved :)
Parts are readily available, as over 2 million of these were produced. These were made to be taken apart, fixed, and put back together. Getting familiar with replacing fuel filters and doing the valve adjustment yourself will save you some $$$. No chintzy plastic clips holding door panels on. The doors sound like a bank vault when shut. These definitely have a soul.