I am wanting to purchase an older Mercedes diesel car just as a Daily Driver( something that wont stop working every 10 secs like my 560 sel and that i can get for about 800 running)

I dont know much about the diesels , but i know that they last a long time and get great MPG's .

What should i look for when trying to purchase one ?
Is it smart to buy one with over 250k on it ?
Can a amature mechanic work on this car ?

What are the common problems with these cars ?


Please let me know anything and everything i need to purchase my diesel !

Thanks