Two Comments:
1. Yes, the first time I heard that sound I thought we were in big trouble. It only happens under certain temperature/climate conditions, and very rarely, but the first time...WOW!
2. Last September we had an even more alarming sound coming to the top of a pass in Colorado. It quited down on the way down, but then began again on the flat. Long story -- short version: We stopped at Paul's diesel service in Blanca, Colorado. He found that the shroud had completely fallen into the fan and we were close to catastrophy. Fortunately there was a little RV park right across the street and the parts came in by UPS the next day. Fan and shroud replacement all cost about $375 (as I recall.) The good news: GM took care of the entire bill as I was still under the 36,000 mile bumper to bumper warranty.
Paul said there were NO bolts left holding the shroud.
Ours is a 2007 Duramax/Allison.
|