My mechanic will probably have to take the serpentine belt off to do a repair. I guess the belt is a year old, and has 12,000 miles on it. How often should those be changed?

1991 300d 179k

Change the belt when it gets cracks or damage, or when the Vs turn into | |'s

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

100K +/- miles is a good number.

X2
100k is often recomended by the car manufactures & belt manufactures.
Keep the old belt as a spare in the car. Best not to keep a new one as a spare as they deteriorate over time where they are bent & often fail reasonably soon after being installed if they have been left in the trunk for a few years.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

THIS!

I think a one year old belt with 12,000 miles on it would have a lot of life left in it and would make sense to re-use.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

The day before this happens:
http://www.peachparts.com/shopforum/2974916-post112.html

__________________
daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

I had one go a lot sooner than 100k miles on my W210. If they are taking belt off for other reasons, then it should be cost of part to replace. And as others have said, old one could be an emergency spare.

Our W210 belt broke while driving on an elevated expressway with no place to pull off. Temperature was skyrocketing and I had no power steering or battery charging. I turned the heater on (car has electric pump for heater) and this kept temperature somewaht in control until we exited expressway. Luckily it was near our condo. Had to get AAA to tow to dealer for repair. Not a great experience!

BTW, I believe newer belts are better - maybe have Kevlar reinforcing or???

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5

100K or every 3 years--Whichever is sooner.....

__________________
http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

If you replace the belt while it is still good, regardless of miles, you can put it away as a spare, as others have written. If you're capable of doing your own maintenance (Some of us aren't, that's no crime), replace the belt yourself, then you'll know how. It's a lot easier to do something for the first time at home with all your tools and manuals than out on the road in the rain or snow. Even if a mechanic ends up doing the job on the road, you won't have to go looking for a replacement belt and you'll be able to show him how it goes on.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970