Idler pulley noise
My first post on this forum so if I do it wrong, sorry. I think the idler pulley on my 2009 rx350 may be going bad. Started out as a squeal-type noise but that is gone and I think I can hear a rattle-type noise now. Is there any way you can tell if it's the tensioner pulley or the idler pulley? Are there any instructions for replacing them and should I replace the belt too? The car has 70,000 miles on it. If a repair shop does it, what kind of cost am I looking at? Thanks!