Having the dealer look up a part number so you can buy it at another store is poor form. Plus, . . .parts departments can see this type of customer a mile away and will not be helpful. ( nor do they need to be )

Build a good relationship with the parts guys and they will help you more than you realize.

Yes, didn't want to call a dealer for info if I was not going to purchase from him. Alldata lists the part number as 0109978392 but that seems to be a discontinued item. I assume it was changed at some point. Ordered belt from reputable auto parts place...a Contitech belt...sent them my vin and engine number and they say that is the belt for my vehicle.
#0119970692 is the number. Guess we will see.

shaman15, you could have ordered the drive belt from a MB dealer that sells parts at wholesale prices, and have the belt shipped to you. No need to drive 2 hours to your local MB dealer.

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Fred Hoelzle

Yes, hadn't really thought of that. Belt should arrive in a couple of days ..if it is not the right one I will return it and check out a dealer.

I know all about that! Tensioner just crapped out on my 95 E320. The previous owner also removed the smog pump, so figuring out what size belt was "a lot of fun!" Minus the pump, the best size I could get that would work was 93"

To update...Belt arrived..cleaned pulleys .put it on...squeak gone. Correct belt for my S320 was Contitech 6K2225 .
Seems the previous owner had the wrong belt on...old belt was about 3/4" longer and he had made the problem worse by using loads of belt dressing.
My car does not have the mechanical air pump (smog pump) nor have rear AC...takes longer belt if yours has these. Great to have that annoying squeal gone finally !