Maintenance

Checking the serpentine belt for wear

The serpentine belt drives the alternator, power steering, and AC compressor, and a worn or cracked one can snap unexpectedly, so a quick visual check every few months is worthwhile.

Difficulty
Easy
Time
10–15 minutes to inspect
DIY cost
$20–$50
Pro cost
$100–$200

Symptoms

  • Squealing noise from the front of the engine, especially on startup
  • No record of the belt ever being inspected or changed
  • Visible cracks or fraying when looking under the hood

Likely causes

  • CommonNormal rubber aging and crackingBelts typically last 60,000–100,000 miles but degrade with heat and age regardless of mileage.
  • PossibleBelt tensioner or pulley wearing outA failing tensioner can cause a belt to wear unevenly or slip even if the belt itself is newer.
  • Less commonOil or fluid contamination on the beltA leak dripping onto the belt can cause it to glaze and slip prematurely.

What to do

  1. With the engine off and cool, locate the serpentine belt at the front of the engine using your under-hood diagram.
  2. Look closely at the ribbed side for cracks, chunks missing, fraying edges, or a shiny/glazed look.
  3. Twist the belt gently to inspect the underside ribs, where cracking often starts first.
  4. Check that the tensioner pulley isn't wobbling and that the belt sits properly in all pulley grooves.
  5. If you see multiple cracks per rib section, fraying, or glazing, have the belt replaced before it fails.
  6. Have the tensioner and idler pulleys inspected at the same time, since replacing just the belt with a failing tensioner leads to repeat problems.

Tools and parts

  • Flashlight
Serpentine belt for your vehicleSearch: “serpentine belt for [your car year make model]”

When to call a pro

If the belt squeals constantly, looks severely worn, or the tensioner wobbles, have it replaced soon since a snapped belt can leave you stranded and stop the power steering and charging.

Safety

Use caution

Keep hands and clothing away from the belt and pulleys, and never inspect a running engine's belt area with your hands.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.