Take a look below your vehicle’s hood and you will find all sorts of different belts. Though the average person might know what one or two of these belts do, most people understandably do not know exactly what functions the different types of belts provide. Let’s take a look at the different types of automotive belts and explain the unique purposes they serve.

Engine serpentine belt

The Serpentine Belt

Lengthy serpentine belts extend through the entirety of the engine’s components, providing them with power necessary to function. Serpentine belts take the place of the fairly antiquated V-belts as described below. Serpentine belts are standard in all of the latest vehicles, providing power to the engine’s accessories. If this essential belt is damaged or loosens, it has the potential to cause component failure throughout the engine. Thankfully, serpentine belts are easily replaceable. You’ll know if the serpentine belt needs to be replaced when it makes a squeaking noise, is visibly damaged, or when other engine components start to fail.

V-belts

V-belts are the belts that start at the crankshaft and extend through the vehicle’s components ranging from the AC compressor to the power steering pump, the alternator, and the water pump. The purpose of V-belts is to provide power to each of these components. However, V-belts are typically found in older vehicles. V-belts rarely slip from the circuit, and if the V-belt fails, it does not mean the rest of the belts will also fail. 

Engine timing belt

The Timing Belt

Also referred to as camshaft drive belts and Gilmer belts, timing belts serve the purpose of assisting the crankshaft to turn the camshaft as necessary. A belt made of rubber opens engine valves and closes them in a synchronized manner with the pistons. In today’s vehicles, the timing belt provides the same purpose as the timing chain used in the vehicles of yesteryear. If this belt fails, it won’t cause extensive damage to the pistons, ultimately ensuring the engine does not require a full replacement.

Timing belts typically require replacement after 90,000 miles. However, there is the potential for timing belts to last upwards of 110,000 miles or more. Experienced mechanics will replace the water pump in unison with the timing belt as both typically go bad around the same time. In fact, it is prudent to change the water pump even if it is still working at the time the timing belt goes bad as it will likely fail in the near future.

Alternator Belts

An engine in which the alternator is not powered by a serpentine belt is reliant upon an alternator belt. This is a diminutive belt that strictly powers the alternator. There is also the potential for the alternator belt to power the steering pump belt if the engine is designed for such an arrangement. The bottom line is the vehicle’s battery will not remain fully charged unless the alternator belt is properly installed and functions as designed.

Fan Belts

Cooling systems require a belt for power. Serpentine belts are used in some engines while fan belts are used in others. Fan belts provide power to parts within the vehicle’s cooling system including the air conditioner, the radiator fan, and the water pump. Functional fan belts power cooling systems by distributing coolant throughout the vehicle’s engine and also by cooling the radiator. Sadly, if the fan belt does not function as designed, the engine will not be properly cooled, leading to overheating that can result in expensive repairs. This is precisely why the fan belt should be closely analyzed when routine inspections are performed.

Is the Drive Belt the Same as the Serpentine Belt?

The serpentine belt is sometimes referred to as the drive belt. The drive belt serves the purpose of transmitting power to parts around the engine ranging from the air conditioner compressor to the water pump and alternator. When the vehicle engine turns on, the drive belt or serpentine belt is also turned on, transmitting power to the devices listed above in a near instantaneous manner. Older mechanics will testify that the drive belt was previously referred to as a V-belt or a serpentine belt.