So I was looking at a 2004 S500 4matic
and i noticed a couple potential things that might deter me from purchasing.
When I turned the car on, it worked fine for about 3 minutes, I put it into drive and pulled up to the street, stopped, and it started making a little bit of a rumbling noise, the seller told me its the "air pump"? Is this a potential problem? I'm a BMW guy so I know nothing about Mercedes, but am really intrigued by the S class. Also the Navigation screen, along with the radio and stuff, was not functioning? What could this be?

Any help is greatly appreciated thanks.

 

radio is very EXPENSIVE I replaced mine for about 1 grand (USED) every part on the s class is expensive to replace I want to trade my s430 in but i can find anything I like execpt the s550