M116 Alternator Belt Failure (Second!)
 

Hi Guys,

So the alternator belt on my 420SEL with 120A ouptut alternator failed today. It blew apart and rolled one of the PS/Water pump belts over.

The belt is a Contitech (Continental) belt put on by my shop while they did the valve job back in January. It had a little more than 5,400 miles on it.

I had a similar issue last year. The shop replaced all my belts with Continental and a few months later the alternator belt failed. I don't have any hard data on the mileage.

I think the failure might be related to the higher output alternator and the additional load it may place on the belt....or it could have been lose or too tight?

Has anyone else with the higher output alternators run into this problem? My other cars are all serpentine belts so I don't have this issue.

Let me know what you guys think!


---Kris

Generally if the belt is too loose you'll get squealing, especially if the alternator is under a heavy load. You'd probably notice that.

V-belts can fail if they're too tight though or if they're misaligned (say the pulley isn't aligned with the crank pulley). I'd check alignment and tension as a place to start.

You know, a few days prior I thought I heard squeaking... It was very short though so I didn't think much of it.