Rauhbatz

I just turned over 99000 miles...given the frequency the belt tensioner let go on my 1991 190E I'm starting to think I need these two items; and there was some poor chap with a 2004 S class that threw a tensioner when I was at Advance Auto parts last night...helped my local team change it.

Any steer on replacement frequencies would be welcome...just got the Xmas bonus money and want to do an investment to keep our ML purring along...

sosh

If you are speaking about the serpintine accessory drive belt I would change it every 50K, Its cheap. As far as the tensioner that can tell you that its due to be changed when it begins to make some noise. Actually if you feel more comfortable change it when you change the belt as it too is inexpensive. If you are speaking about the timing chain and its tensioner these usually last until the engine overhaul.

Rauhbatz

Thanks for the insights...will get all that done next week! Always pays to be proactive with an MB!