Difference Between Timing Belt & Serpentine Belt

by Chris Carson

Some people use the terms "timing belt" and "serpentine belt" interchangeably. However, these two engine components have entirely different functions. Both play vital roles in the operation of a vehicle and should be regularly checked for wear or damage.

Timing Belt

The timing belt connects the crankshaft of a car to the camshaft(s). Its purpose is to ensure that the valves open and close in sequence with the pistons. Not all vehicles have a timing belt.

Serpentine Belt

The serpentine belt, or drive belt, connects and operates a number of engine accessories, including the air-conditioner compressor, water pump and alternator. Most newer passenger vehicles have a serpentine belt.


If the timing belt breaks while the vehicle is in operation, the pistons could strike the open valves, which may result in damage to the pistons, valves, and/or cylinder head, leading to expensive repairs and possible engine replacement. If the serpentine belt breaks while the vehicle is in operation, everything driven by the belt will cease to operate.

About the Author

Chris Carson has been writing professionally since 1988, specializing in topics such as cats, jewelry, history and English. Her articles have appeared in "Best Friends Magazine" and on various websites. Carson received her Bachelor of Arts in English from Arizona State University.

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