I noticed a thumping noise today while driving home. when i popped the hood i noticed that a pulley was wobbling. its the one closest to the top behind the fan. i know the owner b4 had the fan clutch replaced recently. could of been shoddy work by the mechanic. Anyone know what pulley i'm talking about? and what size bolt it is? can i just tighten it back up or does it require a specific torque? will i be able to tightn it up with a regular socket wrench (will it fit in such a cramped spot?) Any help would be great. thanks in advance!

Ed.