Serpentine belt / change interval ?
 

Given the age of my car ( 6 years ) & mileage ( 90 k miles ), I was considering installing new serpentine belts.
Original belts don't really show any wear signs but, as they say in the movies " Prevention is the key ". ;)
What are the collective opinions ?

look at them and see if they are cracked across the ridges

I just replaced mine a week ago when it broke.
17 years and over 400,000km on the original belt.
1989 260E

replacing serpinteen belt
 

You might as well order a tensioner and shock with your belt. I got mine from Phill at fast lane . I have a 1992 300-E . When a friend of mine replaced the belt the first time , we found after that the tensioner was bad and the tension started to slip. We had to reinstall the belt no damage but with a new tensioner

I do not know what model and year you have . I would highly recommend you look up the proceeder for your model and year. Buy the way on my car you have to remove the fan shroud and the Visous fan first to get at the belt and tensioner. IT may be a good time to replace or check the visous coupler on your fan if it has to come out. Why do the job twice.

Bob Geco

I once had a low-mileage, 12-year-old car that started squealing during startup. I noticed that the belt looked fine, but the records showed the belt was original. Further examination showed the belt was stretched to the limit of tensioner travel -- verified by comparison with a new belt.

So beyond a visual examination, check the belt for stretch.

MB does not say when to change them. The official line is to inspect them and replace when they start to crack. If you look at where the tensoner pushes against the back of the belt exposing the rids, you will see cracks if the belt is tired. If you don't see any cracks, its fine.

I know several that have lasted quite awhile, my friends 97 S320 still has the original. But it has small cracks starting and is due soon. My other friend changed his at about 145k on his E300D.


You do not want to have one break though, not only will you be stranded. But it could do a bunch of damage to other things. My friend had the serp belt fail on his 735IL awhile ago, original belt car was 8 years old at the time. Belt failed on the highway and ripped the upper radiator hose off the neck, snapping the neck of course. So insted of just replacing a $40 belt he had to replace a $500 radiator, plus a cooling hose, plus coolant, and the $40 belt.

Thank you all for sharing your opinions/experiences.
Being, as I said, anal about preventive maintenance, I got 2 new belts, installed them & stored the old ones in the trunk with the sparetire.
When I scrutinized the old belts, they showed a lot of age-cracking.
Heck for $ 50.00 bucks what do I care. ;)
Look at the bright side of it, it wasn't a waste of time & I have piece of mind.

No it most certainly wasn't a waste of time. If you are keeping the car long enough you would have had to do it at some point.

Whats the difference in changing it today vs 18 months from now?

It's good to be that way ... when there's something to prevent.

Mercedes are a little better than American stuff, of course.

Best preventive maintenance is to inspect often.

The belt needs to be changed if there are more than 5 cracks in an inch. While changing the belt, also check for noisy bearings in the idler pulleys.

How easy is the belt change? Is it something you can do yourself on a 99 S320? I have changed many belts on my 300SD but they are standard Vbelts rather than Serpentine.

Don't know about your car, but changing both belts on mine ( first time ) it took me about 15 minutes.
The belt routing should be shown in your owners manual ( check to be sure ). ;)

Richard, how easy depends on your level of comfort working on cars. It's all nuts and bolts and a bit of ingenuity getting the belt on with only two hands. Manny made a good suggestion with the belt diagram. If you can't find one, draw one before taking the old belt off.

Don't know about your car. I was looking at my friends 97 and it seems to have more then one tensoner. I'm sure I could figure it out either by looking at it enough or digging up the procedure somewhere. His is cracked to, next month maybe I'll get him to change it.

I think once you get the fan shroud and fan out of the way their will be more room. The top part of the front crossmember comes right off to.