How do you change the AC compressor belt on a 2008 Subaru Impreza 2.5i motor?

To change the AC compressor belt on a 2008 Subaru Impreza 2.5i, first, disconnect the negative battery terminal for safety. Then, loosen the tensioner pulley by using a wrench on the tensioner bolt, which will allow you to remove the old belt. Route the new belt according to the belt diagram typically found in the engine bay, ensuring it sits properly on all pulleys. Finally, re-tighten the tensioner, check the belt alignment, and reconnect the battery.