Defective Timing Belt Tensioner Bolt - Anyone Else Seen One?

jaluhn · Post by **jaluhn** » 10 Apr 2009, 00:48

I had an 04 S60 come into my shop a couple days ago complaining that the motor suddenly stopped while driving. Turns out that the timing belt tensioner bolt had failed, causing the belt to go slack, which then led to the classic piston / valve interaction.

What caused it all seems to be a defective tensioner bolt. The car has ~75K miles on it, and to the best of the owner's knowedge the timing belt had never been off. Visual inspection of the belt, bearings, etc supports that conclusion as well, since everything appears to be original. The bolt failed from a fatigue crack in the threaded section of the bolt apparently just below the block surface. Once the crack propagated sufficiently the bolt snapped, wit obvious results. I do not have sufficient equipment to look closely enough at the failure surface to be sure, but it appears that the failure initiated at a defect in the bolt.

My question is if anyone else has seen or heard of a similar failure in one of these cars. I am 99% certain this represents a manufacturing defect with the car, and am curious if there have been any other instances.

Also, does anyone have any ideas on who to contact with Volvo to discuss this failure with? The car is out of warranty and the owners of the car do appear to try and make Volvo take responsibility for the problem, but I do think someone should be advise of this problem, especially if there have been other failures.
Thanks ~ John

Post by **MadeInJapan** » 10 Apr 2009, 10:12

John,
I read about the same exact thing on V.S., I believe and so far, Volvo USA was not taking responsibility for it. If I recall, part of the problem was inability to verify that it was indeed related to the original tensioner because, like you, the tensioner was dealt with at a non-Volvo establishment. If I find the thread again, I'll post it's link back up here.

jaluhn · Post by **jaluhn** » 10 Apr 2009, 12:52

Thanks.

Also, this was **not** a defective tensioner, but rather the bolt. I have heard of problem with the tensioneror idler bearings prematurely going bad, but this is something different.
~John

Post by **MadeInJapan** » 10 Apr 2009, 15:28

I understand...
Then maybe I was reading about the tensioner and not the bolt. Let me see if I can find that thread I was speaking of earlier.