We found a Mercedes that we liked for $4600, but the dealer was in a town 1.5 hours away. We asked them to bring the car to their Lancaster lot and as long as there wasn't anything major wrong with the car, we would take it. They couldn't bring it down for about a week -- she said they had to replace the air-intake valve.
We met at the lot on Friday 2/6. There was a lot wrong with the car. The seat controls on the driver's door were pushed into the door and couldn't be used. The rear view mirror was loose and could not be adjusted into place. There was a whine in the engine compartment that sounded like a power steering pump going out, but sounded like it was coming from further forward in the engine compartment from where the steering pump is located. The valence below the front bumper was cracked and held together with electrical tape. The inspection ran out at the end of February. The car was filthy.
We didn't want the car in this condition, but told them that if they agreed to fix these things we would be happy to renegotiate the price, within reason. For the next three weeks I was in touch with them by phone, checking on their progress. They agreed to do the work if I would pay for the parts. I agreed, and the price went up by about $400.
Finally they brought the car back to Lancaster on 2/27. The driver seat switches, the mirror, and the valence had been fixed; but the engine whine was still there and they hadn't done the inspection. The car was still filthy. We had had enough of dealing with these clowns and decided to take the car and have it inspected ourselves.
Our mechanic found a number of things wrong with the car that had to be dealt with for inspection -- a tie rod on the passenger side, an AIR INTAKE VALVE (remember the original delay was because they had to replace it?) that had to be replaced to pass the emissions test, and the 'whine' was being caused by a faulty pulley on the serpentine belt. These repairs combined cost $1100.
Our mechanic also found an oil leak 'in the front of the engine, near the cylinder head.' They said they were uncomfortable attempting to find/fix that and that I should take it to someone more experienced with Mercedes specifically. The estimates I've gotten to repair that leak thus far ranged from $1500 to $1800.
One other thing -- the ad for the car said it had heated leather seats, it does not.