serpentine belt

I just replaced my alternator, unfortunately I broke the upper mount bolt and had to drill it out and replace the bolt. Now I have the new alternator in place and bolted up and now the serpentine belt is loose, replaced with a new one and is still loose. I have double and triple checked the routing of the belt is correct and is still loose. The tensioner is working fine, but I still have so much slack in the belt that while the engine is running the belt does not move. and I could almost take the belt off without moving the tensioner. Any suggestions would be greatly appreciated.

 

Before you replaced the alternator was the belt tension good, unknown, or bad? You may have (always) had a belt tension issue which was diagnosed as an alternator issue.

 

The tensioner was fine when I removed the belt, and the alternator was tested before removal with a bad voltage regulator, so that was the need for replacement.

 

Possible the new belt is not the correct one.

 

This has to be it.

Should be a significant amount of tension on that belt