it is actually really easy. my mechanic friend says that when the bearing goes in the pully (the sound that you hear) it is usually a good idea to replace the tensioner while you are at it. all the tensioner is is a spring. but if you just replace the pully know this, the righty tighty, lefty loosy thing does not apply here if you try to loosen the bolt by turning it left all you are doing is releasing tension from the belt and tighting the bolt. the bolt in there is a reverse bolt (dont know the exact technical name) and to loosen it you need to turn it right. seems weird but this is the way to do it. i had to do it myself.
if ya got more questions i will be happy to answer
