belt tensioner

[honerboys]

so i installed a new serpentine belt the other day - this morning the tensioner pulley bearing explodes - hmmmm ...a coincidence ? - i'm hoping so - anyway the plastic pulley was completely melted off the bearing - i looked online and some pictures of the pulley have the grooves for the belt and some don't - does it make a difference - i would think the grooved ones would keep the belt on better than the smooth one - and i'm assuming they are all the same size in diameter?? - if anyone has or can take a picture of theirs i'd appreciate it - thanks