Stripped Upper Tensioner Arm Bolt Hole Threads
 

My teenage son and I are changing the timing belt on our old Mazda 626 so he has something to drive in college. Unfortunately, I believe we cross-threaded the top bolt of the tensioner and stripped the hole's threads. Ugh! What is the best way to recover from this, especially since there is not much space to work in that area?

I'm not familiar with that engine so I'm not entirely clear as to how much room you have, but have you ever seen or used Helicoils? It doesn't take a ton of room to make them work but you do need to take your time and be careful. I've used them several times to rescue stripped out manifold bolts in aluminum heads and had good success with them.

Yeah, there's not much room at all down there. Maybe 4 1/2 inches or so. We ended up getting a helicoil kit, cutting off the back end of the drill bit, and very carefully holding the drill bit in place and turning it slowly while the other person applied pressure to the back of the drill bit with a crowbar. In that way, we slowly and carefully drilled out the old threads. Then we carefully tapped the hole and installed the helicoil. After cleaning (blowing) everything out, we were able to torque the bolt.

Thanks for the idea to get us going, Radioflyer90!