2002 WRX, has been running great before and after this noise appeared. It started yesterday when I left work and started home (it was maybe -2F ambient?), went away after everything warmed up... but now it's back again this morning. It sounds strongest behind and underneath the AC unit and goes away when you throttle up a bit. I'm thinking (but praying otherwise) that it's not timing related... even though it sounds sorta belt-train bearing related. Timing belt and water pump was replaced at Walser Subaru by the PO ~25,000 miles back, but from the invoice I don't see anything about billing for the tensioner or any of the idler bits. Oil levels are good and nothing funny there (replaced ~2,000 miles back.) I'd appreciate any feedback before I go buy $200 in timing bits and spend a cold afternoon swapping parts. Video of noise: https://www.youtube.com/watch?v=myJBc3hGhzY
Crisis averted! I cancelled some plans so I could check all the easily accessible belts and it was just the stupid AC compressor tensioner. That should be a cheap little bit, maybe Grimmspeed even has something shiny I can put there. That gives me like +20hp if I leave the belt off for now, right?
REPLACE THE TENSIONER BEFORE PUTTING NEW BELT ON!!!!!!!!!!!!!!!!!!!!!!!!! mine seized blew up and rubbed a hole in the timing cover and the broken belt got sucked into the gears causing skipped teeth. $3500 later i have a running new motor. new tensioner is $50
Yeah, I usually replace everything that touches the timing belt when I normally change them, but I can't vouch for the shop that did the work for the PO though. :/ Perhaps come summer (barring further noises) I'll pull the timing cover and check everything out, looks like the timing belt is pretty straight forward on this beast once you get the radiator out of the way and you can get the Gates kit that comes with the belt, tensioner and all the rolling bits for around $200.
