What does a drive belt (or serpentine, fan or alternator belt) do?

The serpentine belt (otherwise known as drive belt, fan belt, alternator belt or v-belt and made from rubber) drives a range of ancillary components off the crankshaft of the engine. It transfer power to components like the alternator, the air conditioning system and the power steering unit. Importantly, without the serpentine belt the engine cannot function properly. Modern cars will usually have a single belt to drive its ancillaries, older cars usually have a number of belts to achieve the same thing.

How do you know there is something wrong with the drive / serpentine belt?

• When there is a squeaking noise coming from the engine bay.
• When the steering is heavy (due to a non-functioning power steering system).
• When the battery warning light is on.
• When the engine temperature light is on.

When should you consider having your drive / serpentine belt replaced?

It is crucial that the belt is in tip-top condition, if the belt is neglected there is always a risk it might snap at some point. Over time, the belt can become brittle due to heat from the engine and general wear. It might be that cracks start to appear in the belt. It is at this point that there might be a risk that the belt will snap. If not addressed this can ultimately lead to internal engine damage as, in some cars, the belt also drives the water and oil pumps.

The serpentine belt normally needs to be replaced as and when stipulated in the service schedule of your car (as supplied by the manufacturer). If you find that cracks have started to appear in the belt before the next replacement is due, it is, desirable to get in touch with a mechanic and have the belt replaced to be on the safe side. It will avoid further, more expensive, repairs to your car.

What happens during a drive / serpentine belt replacement?

• Mechanic will inspect the serpentine belt for wear and cracks.
• Mechanic will also check the belt's pulleys and tensioner.
• If necessary, the mechanic will replace the belt (in some cases more than one belt.
• If necessary, the mechanic will advise if other repairs are necessary.

How much does a drive / serpentine belt replacement cost?

The cost of a serpentine belt replacement depends on your car and what parts your car's manufacturer recommends using for the replacement. Find out what you could save by having your serpentine belt replaced by Clickmechanic, by selecting your car at the top of this page!