Good and bad idler pulley sounds on a Jeep JK. The pulleys on a Jeep JK are known to fail so I inspect them as part of regular preventive maintenance. With the stethoscope the tensioner pulley has an obvious bearing click. The click could not be heard without it. Once removed the pulley also had play in the bearings, another sign of wear.
The pulley is a $15 part and are simple to replace. If they fail you are likely stuck on the side of the road. Or worse stuck on the trail. A pulley failure can also shred a fan belt.
I used a stethoscope and cell phone to record the video. I just removed the ear pieces and held the open end near the microphone on the cell.
Tags: Good and bad idler pulley sounds on a Jeep JK