Clean the pullys with a wire brush?
A little packed grit, salt, dirt in the pulley grooves will keep belt from seating properly...
A little lube on the tensioner and work it a few times? Salt corrosion/crust can limit its travel. Both can cause a new belt to glaze up quickly...

Did you wiggle your pullys when the belt was off to see if you have a bad bearing somewhere?

-OMotS


"If memory serves fails me..."
Quote: ( unnamed) "been prtty deep in the cooler todaay "

Television and radio are most effective when people question little and think even less.