Loud Squealing - Belt Tension Spring Broke!

[tankowner]

So my wife comes to pick me up today driving the '95 E300D. I can almost hear the car before I can see it, the belt is squealing so loud. Oh great, what is this new surprise. The car seems to be running okay, so I just drive it a mile and a half home. Upon inspection the serpentine belt is way too loose, then I notice the spring that holds the belt tensioner pulley is missing . What the? only the top hook is dangling there and the rest is who knows where. I guess I'll be replacing the spring, but why would this happen? Do you think there is something more to this, or did the spring just give out. The belt is good, I replaced it about 8 months ago.

You can see the one I am talking about below - #107. This is the spring that can be leveraged up so that the bolt that holds it on the upper end can be undone and then the spring lowered to release the tensioner when you need to remove the belt. I can post a pick of the remaining piece if necessary. The spring on the car doesn't actually look like the one below (all spring-like), i think it had a protective plastic housing around it.

[Brian Carlton]

The springs do fail on occasion.

Usually, the loss of the spring causes extreme slippage in the belt. So, you might consider replacing the belt when the spring is replaced.

[tankowner]

Originally Posted by Brian Carlton

The springs do fail on occasion.

Usually, the loss of the spring causes extreme slippage in the belt. So, you might consider replacing the belt when the spring is replaced.

Thanks Brian. Looks like I will have to pay a visit to the dealer tomorrow and see what they want to charge me for one - I can't really wait for one to arrive via mail.

Part number on this is 606-993-03-10 - just in case anyone needs it for future reference.

[Brian Carlton]

Originally Posted by tankowner

Thanks Brian. Looks like I will have to pay a visit to the dealer tomorrow and see what they want to charge me for one - I can't really wait for one to arrive via mail.

Part number on this is 606-993-03-10 - just in case anyone needs it for future reference.

I'd call first. The dealer's stock on older vehicles is quite thin. You might get better service from Fastlane at a more attractive price.

[nhdoc]

Here's a tip...for those of us who have the same arrangement, change your spring before it breaks as a sort of preventive maintenance when you change the belt (it is relatively cheap) and throw the old one in the trunk, along with the old belt, and this way if either breaks you won't be stranded.

You might just want to check all of the pulleys and the a/c compressor to make sure nothing is seized up too. That can cause the spring to stretch, depending on the location of the seized pulley.

[tankowner]

Originally Posted by nhdoc

Here's a tip...for those of us who have the same arrangement, change your spring before it breaks as a sort of preventive maintenance when you change the belt (it is relatively cheap) and throw the old one in the trunk, along with the old belt, and this way if either breaks you won't be stranded.

You might just want to check all of the pulleys and the a/c compressor to make sure nothing is seized up too. That can cause the spring to stretch, depending on the location of the seized pulley.

Thanks Marty - that is a good tip. I changed the belt out about 8 months ago before the old one was shot and then, as you suggested, I put the old one in the trunk. I never even thought about the spring though. I will have a look at the pulleys - when I first heard the squeal, I was afraid that something had seized up - like the alternator, so good to check that out too. Thanks.

[Chris W.]

The only saving grace is that it is a cheap part and very easy to replace. I replaced mine as a preventative measure when I did the tensioner "shock" and belt, but my car had about 250K on it at the time. (the belt didn't have that mileage, however!)

Rgds,
Chris W.
'95 E300D, 296K

[sasquatchgeoff]

It is not a bad idea to replace the spring and "shock" (tensioner damper) at the same time - kind of like the left and right headlight. - once I replaced the damper alone and it wore out much too quickly. The two components work together and are good for about 50K miles.