What is an alternator belt or drive belt?

An alternator belt is known by many names including the drive belt, fan belt, v-belt or a serpentine belt.

Made of rubber, the belt is prone to deterioration over time, and due to its position next to the engine, excessive heat and general wear will lead to a brittle drive belt that is prone to cracking.

How long should an alternator belt last?

A simple rule of thumb for the lifespan of an alternator belt is around 3–4 years.

It should be inspected at your vehicle service or whenever you have an oil change.

What does an alternator belt do?

The alternator belt’s job, or drive belt, is to transfer power from the engine crankshaft to various other components; these include the alternator (of course), the air conditioning and the power steering.

Older cars had a selection of belts to take care of these tasks, but modern cars need only one. It’s an essential part of the healthy running of your engine, so it’s imperative it’s in good condition.

In many cars, the alternator or drive belt will drive the car’s water pump and oil pump, and if these are left to fail or malfunction, it can lead to severe or fatal engine damage.

Severe engine damage can mean the end of your car’s useful life, or raise some of the most substantial costs associated with vehicle repair.

What is an alternator belt tensioner and how does this work with the alternator belt?

The belt tensioner is responsible for the tight fit of your alternator belt. If it doesn’t fit correctly, there’s a danger of it slipping and failing to perform properly.

The tensioner is a small pulley that applies pressure to the outer of the belt, ensuring smooth, reliable and consistent running.

The drive belt tensioner can be infiltrated and affected by dirt gathered from an old belt or by being thrown up from the road.

If given a chance, this dirt can penetrate the tensioner and cause it to seize—becoming ineffective and leading to unwanted damage to your engine.

What does an alternator belt replacement cost?

Typically, an alternator belt replacement cost in the UK will be around £100–£200 from a registered dealer. Other garages will charge less for a new alternator belt with prices often at around half the dealer rate.

Car make and model Fixter price Instant savings

0.6 litres

£131.30 17%

0.9 litres