So I just bought my first car, which was a 1979 300sd for $3500. The major problems I have found by driving it are as follows:
-leak in radiator or radiator fluid line
-rear driver side door doesn't open from outside
-fuel leak
-driver door not working
-A/C not working
I have no clue about diesel cars or Mercedes cars so i have no clue about the workings of this car. I was wondering if any of these problems were common with this kind of car and if so, what is the cause of these problems? also, the previous owner put some aftermarket headlights on the car and the passenger side light is broken, so i was wondering of good websites to find a match to this kind of headlight to replace it or a good website to just buy the stock style headlight to replace both of the lights.

Thanks for all your helo, i really apreciate it