What Is a Serpentine Belt? Definition, Meaning and Concept

Take a look under your car and chances are you'll find a belt or system of belts attached to the pulleys at the front of your engine. If there is only one belt wound through several different pulleys, you are looking at a serpentine belt. The serpentine belt is different from other types of belt systems because the serpentine belt is a long, continuous belt that is connected to several different devices. Older systems employed the use of numerous belts to drive devices in the engine compartment, but after the development of the serpentine belt in 1979, most automobiles began using the system for efficiency and ease of use.

Peripheral devices such as the power steering pump, alternator, and air pump all connect to the belt systems. In the past, two or three of these peripheral devices connected to each other, but not to all peripheral devices. Therefore, if one of the straps broke, the driver might not be aware of the loss of a device. Because the serpentine belt connects all the pulleys of the peripheral devices, the driver will quickly notice if the belt breaks because all the peripherals, including the power steering, will suffer or shut down completely immediately.

Serpentine belts are much easier to install than individual belts. There is usually a moving pulley that puts tension on the serpentine belt, so replacing the belt simply involves loosening that pulley, removing the old belt, replacing it with a new serpentine belt, and tightening it to the proper specs. Older systems required a mechanic to identify which belt was broken and work around other belts and engine components to replace the belt.

Serpentine belts are less likely to stretch and break than smaller, weaker individual belts. Tension is more evenly distributed throughout the belt, reducing slippage and stretching. Because serpentine belts are typically longer, larger, and wider than individual belts, they tend to last longer and resist frequent breakage.