The serpentine belt is so named because of the way it "snakes" around the engine. One belt often drives several accessories.

Serpentine belts are normally kept tight by means of a spring loaded belt tensioner. The tensioner, has a pulley that contacts the belt and a spring loaded arm which applies tension to keep the belt tight.

Serpentine belts last much longer than the old V-belts. One reason is their thin cross-section makes them far more flexible.

Another is the tensioner tends to keep them in proper adjustment. A typical serpentine belt can last five years or more. Some newer belts are made of Ethylene-Propylene-Diene-Monomer (EDPM) and last even longer. Inspection is the key to knowing when to replace. The serpentine belt should be inspected at least annually or at the sign of a problem. The leading symptom of a problem is a rotational squeak or squeal, especially first thing in the morning.

Small cracks in the ribs of the belt do NOT indicate a need for replacement. These are fairly normal and do not weaken the belt.

Deep cracks and pieces missing from the ribs indicates the need for immediate replacement.

Fraying or separation of the cords from the backing does indicate a need for replacement of the serpentine belt.

The back of the belt also wears. When the backing is torn, cracked or separated, the belt should be replaced.

In my opinion any belt seven years or older should be replace, even if it looks okay. At this point, any future savings will be outweighed by the risk. If the belt breaks, the vehicle will normally be disabled.

  A squeaking or squealing belt indicates a problem

  Belts last a lot longer than they used to, often five or more years

  A serpentine belt is NOT the same as a timing belt

  For lowest overall cost replace belts that are seven years or more of age

If you are not sure about your serpentine belt, have the professionals at AGCO inspect it for you. AGCO, it’s the place to go.