Replace your fan belt.

A fan belt (also called the auxiliary or serpentine belt on modern cars) drives the alternator, water pump, power steering and air-con compressor. A failed belt is a roadside breakdown waiting to happen — typical UK replacement cost is £70–£180 at an independent garage, or £200–£400 at a main dealer for premium brands.

The job itself takes 30–90 minutes for a competent mechanic. Most cars have a single serpentine belt these days; older or pricier cars may have a separate belt for the air-con or power steering, which adds £20–£60 per extra belt.

Symptoms of a worn or failing fan belt

• Squealing on cold start — the classic giveaway, especially in damp weather. A glazed or stretched belt slips on the pulleys until friction warms it up.
• Battery warning light — the belt drives the alternator; a slipping belt means the battery isn't being charged properly.
• Power steering going heavy — particularly noticeable at low speeds and parking manoeuvres.
• Visible cracks, glazing or missing chunks — pop the bonnet and inspect the belt face. Hairline cracks across the ribbed face mean replacement is overdue.
• Engine overheating — on most cars the belt drives the water pump; a failed belt can lead to overheating within minutes.

Typical UK costs

The fan belt and the cambelt are different things — don't confuse the two. The cambelt drives the camshaft and is buried inside the engine; replacement is far more expensive and is mileage/age driven, not condition-driven.

Should the tensioner go at the same time?

Almost always yes. The tensioner pulley keeps the belt under correct load, and tensioner bearings wear at a similar rate to the belt itself. Replacing the belt without the tensioner is asking for a return visit within a year. Add £40–£90 for the part; minimal extra labour as it's already exposed.

Mobile vs garage

For a fan belt, a good mobile mechanic is often cheaper and quicker than booking a garage slot — provided your car parks somewhere with enough room around the bonnet for tools. Most mobile pros do the job in your driveway or workplace car park in under an hour.

Things people often miss

• Routing — modern serpentine belts have a specific path around 5–7 pulleys. Get it wrong and pulleys turn the wrong way; some cars are forgiving, others not. Take a photo before removing the old belt.
• Belt squeal isn't always the belt — a worn idler pulley or seized A/C compressor can cause the same noise and burn out a fresh belt within weeks. A pro will check pulley bearings while it's apart.
• Don't over-tension — most modern cars have automatic tensioners; on older cars with manual adjustment, over-tensioning shortens belt and bearing life. Half-inch deflection at the longest free run is the typical spec.
• Engine bay covers — newer cars often have an engine cover and undertray that need removing for access. Add 10–15 minutes to any DIY estimate for these.

Frequently asked questions

Want a local pro to handle this? A mobile mechanic or independent garage will fit a fan belt in well under an hour. Worth getting it done at the first squeal rather than waiting for a roadside breakdown.