Automotive Diagnostics, Torque & Trailer Wiring

How do you test a spring-loaded Serpentine Belt Tensioner for internal dampener failure?

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 Correct IncorrectUsing a long tensioner bar, pivot the arm: it should move smoothly with stiff resistance and zero binding. With the engine idling, watch the arm: excessive fluttering or rattling indicates a dead dampener.

How do you test a spring-loaded Serpentine Belt Tensioner for internal dampener failure?

• Spray water on the belt while revving the engine
• Measure the belt temperature with a fever thermometer
• Check for smooth arc resistance without binding, and watch for excessive fluttering/bouncing at idle
• Smell the belt rubber for burning toast odor