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Serpentine Belts, also known as Poly-V, Multi-Rib, Multi-V or Poly Rib belts, are the unsung hero of your car's engine. This single, continuous belt is used to drive many components, including your vehicle's alternator, water pump, power steering pump, air conditioning compressor, air pump and more.



How Does it Work?

  • The belt transmits power from the crankshaft or engine to all front end accessory components.
  • Belts are still one of the most efficient ways to transmit power.
  • Drives many components in your engine.
  • Primary function supplies power to the steering system, water pump, air conditioner and alternator.

How Is It Made?

  • Serpentine belts are made of EPDM, an extremely durable compound used to extend the life of serpentine belts.

Why Does It Fail?

  • Belts are standard wear items and should be inspected at roughly 50,000-70,000 miles.
  • These new EPDM belts resist cracking unlike the older OE belts, but they do wear as they lose rubber like a tire.
  • With the development of the new EPDM belt compounds, the failure mode of the belt is not the same as it was in the past with the previous neoprene belts. The EPDM belt will not exhibit rib cracking, even when reaching 80,000-100,000 miles.
  • Even though the ribs may not show cracking, the rib rubber will wear down, resulting in a decreased ability to pull the accessory torque loads.

What are Symptoms of Failure?

  • Slipping, chirping or squealing noises coming from under your hood.
  • One of the systems supported by the serpentine belt fails, such as your battery drains or your vehicle loses power steering failure.
  • Check Engine Light (CEL) illumination.

What Are the Consequences of Failure?

  • All functions supported by the serpentine belt immediately stop working.
  • Vehicle stops working.
  • Loss of power steering, air conditioning.
  • Damage to additional components and/or engine.

If you have questions or concerns about serpentine belts or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.