1) Could be the wrong belt
2) Might not have the belt properly located on one of the pulleys - any side force on the belt will throw it off.
3) the tensioner could be losing it's strength allowing too much play in the belt.
I would suspect one of the first two to start with, it is very eazy to missl one pulley/belt position (belt not in the right set of grooves or too far trom center of the pulley drive surface.
Good luck!
2) Might not have the belt properly located on one of the pulleys - any side force on the belt will throw it off.
3) the tensioner could be losing it's strength allowing too much play in the belt.
I would suspect one of the first two to start with, it is very eazy to missl one pulley/belt position (belt not in the right set of grooves or too far trom center of the pulley drive surface.
Good luck!