2002 S80 - I just replaced my timing belt, idler, water pump, and tensioner, but I'm having issue with the tensioner. I set it up so the "pointer' is in the middle 68°F. I push on the belt to make it moves to the right and then moves back to original position. I turn the engine over manually and test it again. Everything works fine. I run the engine to operating temperature and I shut down the engine. I check the belt immediately and it's loose and the pointer is to the right.

It's suppose to move to the right as the engine gets warmer and it should return back to the place I set it. My question is the belt suppose to get loose when it warms up?

 

It's not returning to center. It's 80°F and the pointer is still all the way to the right and hasn't moved to the center.