For those that have the SL400, does your engine have different sounds when decelerating and at idle? This is my first Mercedes and first V6 so I am not familiar with the normal sounds. One dealer says it is the direct injection system but my BMW has direct injection, albeit with an inline 6, and it sounds the same all the time. My SL engine at times sounds like it has a bad water pump or perhaps a bad turbo. Any input would be welcome.

 

I’d have thought that it is normal for the engine to sound different when decelerating vs idle!

 

HaHa. True, but there is a sound that comes on when decelerating similar to a bad water pump and then goes away when the engine comes to an idle. Dealer says it's normal. I only hear it when the top is down.

 

I’ll have a listen when I next drive mine. I’m usually tuned in to the exhaust sounds.