LexBrett2

Notice that the plastic portion of the pulley is GONE!
Driving to my parents Christmas Eve, I noticed a clatter sound from my engine. My power steering was gone and alternator light came on. I still had power on gas pedal. Fortunately was just a mile from the house. I opened my hood and to my great surprise my drive belt was shredded. Then I looked at the tendioner pulley and it was in gone! No plastic portion of the pulley at all! See pics! Im going to the dealer Monday to get the pulley and belt!

RedGray

Ouch!
I'm glad you didn't have to go far!

On the M271 engine, there's one serpentine belt, and it also drives the water pump. So, when that belt goes, there's no water pump, and there's near zero cooling of the engine (just by heat conduction in the stationary water - there's very little convection).

Fwiw, for others, what the typical belt, pulleys, and belt routing looks like.
The water pump is under the big pulley with the 4 bolts.





Back to wrapping presents...

B3Hulk

https://mbworld.org/forums/c-class-w...placement.html

LexBrett2

Hi all thanks for your help and merry Christmas. Fortunately I had beer in my car as well my tools. Upon further inspection, the supercharger baffle came loose and clearly rubbed against belt causing shredding. But I have no idea why the tendioner pulley disintegrated..

LexBrett2

Removed the supercharger baffle today (while drinking my xmass beers) to find it was loose and clearly rubbed again the belt that caused it to shred!!

LexBrett2

Found the broken pulley in my engine compartment when I was repairing my car. What could have caused this?!

Rocman8

Check the alternator pulley one way clutch by sticking something through the front and try to rotate the inner fins. They should rotate one way and not the other. If they don't rotate at all then it's locked up and causes strain on the belt system. Also check to see if the ac compressor seized up.

LexBrett2

Well I replaced the tendioner pulley and now the car runs great- all the pulleys sound like music. I will check the ac compressor and alternator pulley, but they seem to be working.

LexBrett2

Today my control arm felt intense vibration. I know it was the control arm because the other side went bad a few years ago. So to add insult to injury, I had a second repair this week. On the bright side, the guys at merchants fixed it quickly for a relatively low price.

The mecganic also said that my experience with the bad tensioner pulley is very common, and he repairs 4 or 5 of these a week..

RedGray

That's good to know.
Thanks!

I'm already replacing the tensioner and pulley in my restoration project.

Sounds like a good idea to do the belt, tensioner, and pulley at 50K mile intervals, when I'll also be replacing the timing chain.

LexBrett2

Hey Man,
Does the belt have to be off to check the alternator pulley? Do you just stick a normal flat head screw driver to see if seized? Or need a spline tool? What spline tool?

Rocman8

Belt stays on. Anything that you can reach into the front of the alternator to try and spin the internal fins will work.

LexBrett2

thanks again for your help

B3Hulk

When I changed my clutch pulley on the alternator it was easier then you think. Mine was definitely in a bad way.

watch this video, it will help you to determine if its bad

LexBrett2

Checked the alternator pulley clutch tonight, it was really easy. The clutch went clockwise but not the other way, so I guess the pulley is fine. Many thanks!

Rocman8

Great! How about the ac compressor? Can you spin the center 7mm freely?

LexBrett2

Since my AC is working and the compressor is spinning, do I still need to check it?

Rocman8

If your ac is blowing cold then you are good.