Hey guys whenever I drive my car into my garage I can hear a noise that sounds like a cricket noise and its only audible at low rpms and happens once in awhile. I'm thinking it could be the idler pulley or something with the belts. If I wanted to check and see if it's the pulley, can I just leave all the hoses connected, loosen the belt tension and check and see if its the pulley and then put the belt back on without any problems? Also what is the recommended mileage to replace the pulleys and serpentine belts?

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Main Autos:
1990 BMW 525i
2004 BMW X5 4.4i
2011 Toyota Tacoma Pre-Runner V6