2006 R350 has a VERY LOUD fan in engine compartment when AC is in use (coolant fan I presume). Dealer has no ideas. I have to turn AC off to go through drive-up windows. My neighbors can hear me coming home long before they see me and call my car the 747. People in parking lots stare. This has been going on for years now and even with much maintenance and repairs in other systems is my biggest complaint. I have taken to turning AC off and roasting rather than have people stare and tell me something is wrong with my car. Does anyone else have this issue or know what this is/can it be fixed?