How an automatic belt tensioner works "how the check"

In this video I'll explain to you how an automatic belt tensioner works and how to check if your automatic belt tensioner has failed. And how to check the automatic belt tensioner pulley. #FlatRateMechanic Check out The Flat Rate Mechanics Tool Store on Amazon https://goo.gl/M8MpdC  
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Disclaimer:
Due to factors beyond the control of The Flat Rate Mechanic, it cannot guarantee against unauthorized modifications of this information or improper use of this information. The Flat Rate Mechanic assumes no liability for property damage or injury incurred as a result of any of the information contained in this automotive repair video. The Flat Rate Mechanic recommends safe practices when working on cars or trucks with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this repair video. Due to factors beyond the control of The Flat Rate Mechanic, no information contained in this automotive repair video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.