the head

I waited to see what the cause was before posting, simply because I still have CPO warranty so I just took it in. It was a whine that increased/decreased with engine speed, kind of like a power steering pump that is going out or low on fluid. All I could determine was that it was at the front right of the engine (passenger side). A bad idler pulley was the problem. They did have to order an updated 'engine end cover' as the new pulley assembly would not bolt up to the old cover. And apparently they replaced a leaking valve cover gasket as well. All covered under warranty .

grane

Good post Which warranty do you have?

The idler pulleys are cheap plastic and need replacement at 5 yr/40-50 K mile intervals. This is about time for valve cover and in the M113 engine breather cover gaskets too. Did they replace the belts? If not, i would consider replacing them soon. Keep the old ones in an "emergency kit" in your trunk.

Sounds like they have updated the idler pulley on your V 12, good news.

the head

Yep - I actually replaced the belt myself as part of the 40k service along with the belt tensioner. I do the same thing with the old belt - throw it in the trunk as a spare. Warranty is MB CPO. Still have a little over a year left and it has about paid for itself.

cal1

I have a whining noise coming from the passenger side too. Funny thing is, I only notice it when my wife is in the car.

the head

Nice!