First, you are wrong to think the dealer is your 'dear friend' and has your back 100%. I don't see him willing to give you a loaner, drop the tear down price significantly, etc. Second, tearing down a hardcore commercial blower that blew out after a few months seems like SOP to me. Safety reasons come to mind first. They also want to see what they have done wrong (if anything) in manufacturing for research and design or to correct things in the future.