I had the old belt tensioner out and apart for inspection, here is what I found.

The main body of the belt tensioner, with large 12mm hex center bolt, is retained by ball bearings. The ball bearings are seated between an outer race and an inner race around the large 12mm bolt. Both inner and outer races had a deep wear spot from each ball bearing, adding space between ball, and both races, as much as 4 mm, or more, of space. This is what I was hearing! Click click, clack, click..................

The shock absorber, belt wheel, were OK. But if the 12mm center bolt and bearings were to be let go without replacement, I would imagine the belt would slip off the wheel at some point, but I'd bet I could go another 5k or 10k before the belt would come off!

The belt will come off at 11:25 p.m. with the outdoor air temperature at 10°F. with the vehicle on a road trip and 25 miles from the nearest service station.

Don't forget in a bad area, while it is raining and you are late for something. Fix it, it is winter but remember that belt drives the water pump that keeps that head cool.

A broken belt in a bad area, say on the highway in 100 degree temps could cost a 603 owner $2k-$3k.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

....while the engine is turning 3kRPM and it will throw it off the side of the road into a huge field of grass/straw and you will never see it again......until you have a new one...then you will realize it was in the front cowling

I don't speak from experience, the only belt I have thrown was on my VW

Ya! Ya! Ya! .....

And I was worried that I had to do something immediately!!! but discovered that like the bad engine mount, new one arrived last Friday, the one slightly nailing injector, have six rebuilds waiting, the over due oil change, just bought the little rubber O-rings from the stealer and the 15-50 M-1 Wal-Mart special! They can all wait for January's thau which will be late this year and the ground hog is still sleeping like a log and probably will show up late like everything else..........doom and gloom

On a lighter note Hmmmmmmm?, I doubt the belt tensioner, no I bet the belt tensioner will hold out for the ground hog! Not so: BusyBenz