Drive Belt replacement & repair made easy

Please note that the term auxiliary drive belt is the correct name for the serpentine belt, fan belt, alternator belt and power steering belt.

What is an auxiliary drive belt?

The auxiliary drive belt drives the range of ancillary components used by the vehicle, which can include the alternator, power steering, air conditioning compressor, water pump and still in some rare cases, the cooling fan.

This belt has often incorrectly been assumed that it is the timing belt. The essential thing is, if you can see the belt, it's not the timing belt, it's the auxiliary drive belt!

How does the auxiliary belt work and what are the components?

The auxiliary belt is driven by the crankshaft pulley at the bottom of the engine. It is held firmly against the crankshaft pulley and so when it is turning the belt goes round and turns each of the pulleys on the circuit.

The bet is held fim usually by an automatic auxiliary drive belt tensioner and often there is also one or more guide rollers on the circuit as well to position the belt around the other devices. This is one of the reasons it is also referred to as a serpentine belt, literally because it twists around like a snake.

Alternators are almost always driven by the auxiliary drive belt, which is why it is often referred to as an alternator belt, especially when it breaks, as it’s the usually the most common indication that it has an issue.

The same can be said for the power steering pump, again, this is why it is often referred to as the power steering belt.

In reality, it is usually one belt that drives all the units, but some engines can have two belts to spread the load, especially if routing for one belt is not possible.

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

Typical symptoms of a problematic drive belt include;

• When there is a squeaking noise coming from the engine bay.
• When the steering becomes heavy (PAS pump is not being turned).
• When the battery warning light is on (alternator is not being turned).
• When the engine temperature light is on (water pump is not being turned).
• Any combination of the above!

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

Obviously, if the auxiliary drive belt has broken, it needs to be replaced with immediate effect otherwise the devices on the circuit will not work.

Preventative maintenance is of course advisable and as the belts are relatively inexpensive in most cases and easy to fit, their replacement at regular intervals can prevent future issues.

How common is an auxiliary drive belt replacement?

Unfortunately, it’s one of the most common causes of roadside breakdowns and mechanics are constantly being called out to replace them.

How can I extend the life of my auxiliary drive belt?

Quite simply, you can’t. All you can do is consider regular changes, such as at a full or major service

What happens during an auxiliary 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.
• If necessary, the mechanic will advise if other repairs are necessary.

How much does a drive / serpentine belt replacement cost?

The cost of an auxiliary 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 auxiliary belt replaced by ClickMechanic, by selecting your car at the top of this page!

Please note that the term auxiliary drive belt tensioner is the correct name for the serpentine belt tensioner , fan belt tensioner , alternator belt tensioner and power steering belt tensioner.

What is an auxiliary drive belt tensioner?

The auxiliary drive belt tensioner is a vital part of the drive belt system that runs your ancillary devices such as the alternator, power steering pump, water pump etc.

The auxiliary drive belt tensioner is usually a guide wheel, that has a high tensile spring mechanism, that keeps the auxiliary drive belt tight against the pulleys.

How does the auxiliary drive belt tensioner work and what are the components?

The auxiliary drive belt tensioner is either directly bolted to the engine or to a bracket that is secured in place to the engine. The tensioner usually consists of a flat surface roller, that uses a strong spring to pull the belt tight on to the roller and therefore tight against the other pulleys on the circuit.

How do you know there is something wrong with the auxiliary drive belt tensioner?

• When squeaking noise occurs under the bonnet when starting the car.
• When the belt slips when the engine runs (high-pitched squeaks).
• If the auxiliary drive belt start to resonate or run out of alignment

When should you consider replacing your auxiliary drive belt tensioner?

Whilst it is not always immediately obvious that the issues are being caused by the auxiliary belt tensioner itself, if you have any of the previously mentioned symptoms, then replacement is imminent, if not immediate.

Without the tensioner working correctly, your auxiliary drive belt will cease to function correctly, and that can quite easily end in a breakdown/recovery situation.

How common is an auxiliary drive belt tensioner replacement?

Like any mechanic component that is in constant use, wear and tear will take its toll eventually. Whilst it is not as common as an auxiliary drive belt replacement itself, it’s not uncommon for one to be changed.

How can I extend the lifetime of my auxiliary belt tensioner?

Quite simply, you can’t. It’s a mechanical item that is in use whenever the engine is running.

What happens during an auxiliary drive belt tensioner replacement?

As there are a number of different processes that are required for different engines, some or all of the following procedures will apply;

• Mechanic will check for an unusual noise coming from the engine.
• Mechanic will inspect the auxiliary drive tensioner and other belt pulleys.
• If necessary, the mechanic will then replace the serpentine belt tensioner.
• Mechanic will advise if any other parts need to be replaced, like the auxiliary belt itself.
• Mechanic will test the auxiliary drive belt system.
• Mechanic will make any adjustments if necessary.

How much does an auxiliary drive belt tensioner replacement cost?

The cost of an auxiliary drive belt tensioner 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 tensioner replaced by ClickMechanic, by selecting your car at the top of this page!