My 2000 S430 just started making a very loud grinding noise when I astarted and switched it off. It went on for about a minute after switching car off. It sounded more like it was coming from under the car as opposed to under the hood. I just had the water pump replaced last week but I dont think this has anything to do with that. Any suggestions please. It has 110Kmi

 

hi, i had that same problem recently and it turned out to be my airmatic pump. you need to be a bit more specific about the type of noise you were hearing but my best bet would be for the airmatic pump. The airmatic pump is placed above th drivers side wheel under the bonnet.

 

Manjit, you definately know your merc. Later the same day, I got the following warning: "AIRMATIC" - "STOP - CAR TOO LOW". I just took it in today to get the whole system replaced at a cost of over 4K!