4.3 Volvo V6 Throwing Belts?

Just bought a 2007 StingRay with a Volvo 4.3L V6 (Carb'd). At the 9 hour mark the serpentine simply came off at about 3/4 throttle. The dealer reinstalled the belt, checked the pulleys, and we did a test run for two hours without issue. The next day, the belt came off AGAIN .

Has anyone seen this before? From what I can see the alignment of the pulleys looks OK. My engine stalled the first time that the belt came off. Is there a mechanism built into these motors that shuts the engine down under high stress (like temperature for example)? I am concerned that the stress of running without a serpentine belt, albeit a short period of time, will cause excess wear on the engine and problems in the future.

 

I'm not sure about the tensioning system on the Volvo 6 serp belt, but it sounds like it's not doing its job. Check to see that all of your wheels are spinning freely, check the belt for signs of abnormal wear. Make sure that your tensioner hasn't shifted. Tensioners are usually designed to move a bit, at hig RPM, your belt gets tighter so the tensioner usually slackens to maintain the right tension. When you come back down to idle, the tensioner should tighten up, if it doesn't , the belt might just pop off. Like I said though, I'm not sure how their system works.

 

Thanks for the help Thunderhead. I just got back from the dealer today. It turned out to be the bracket that holds on the power steering pump. It was bent just enough to throw the pulley off alignment. The manufacturer must have hit it on something while they were putting the engine in the boat.