Ok I installed a set of mac underdrive pullies some time ago. Now my tension pulley started whining really bad, so I replaced the whole tensioner assembly. This cured the whine but not for long it started in within a couple of days of the new tensioner. When I would spray wd-40 in the bearing it would stop whining but when it dried started up agian. I replaced the idle pulley thinking it would stop it as well but it did not and I went threw about 3 different new bearings thinking it was a bad one but it whined as a put the brand new ones on. So my question is WTF? No one seems to know why it is doing it and I sure as hell am stumped on this too. Let me know if anyone has any ideas? Thanks.