1997 E420 - engine noise
post a video,it helps.
Don't go to the dealer with a 14 year old orphan model,for surely you will leave lighter in the wallet.
If you can't fix it find a good indie mb shop.
Blower motor, easy just shut off and check
main motor fan just unplug it to see if it is the culprit
catalytic converters have started to break lose?
Need a lot more info to diagnose, ie, is the car moving or stationary when this occurs? Location of sound? Increase or decrease with speed if moving, etc.



