An alternator is like a generator in your car. It takes the mechanical energy created by the engine - and converts it into electrical energy via magnetic coils. That electricity keeps your car’s battery charged and powers everything from the lights and locks to the entertainment system and engine control unit (ECU).
Without a working alternator, you would not only be without all your essential electrical components - but your battery would also drain rapidly, leaving you with no engine power at all!
Obviously, you’ll want to avoid this, whether you’re looking to sell your car or not. In this guide, we’ll cover the warning signs of a faulty alternator, how you can make yours last longer, and how much it costs to replace one.
We’ll also explore the benefits and drawbacks of DIY alternator replacement.
Get a free valuation
Signs of a failing alternator
If you have an ailing alternator, you’re likely to notice issues with your lights before anything else. The headlights, interior lights, and dashboard warning lights could start to dim, flicker, or fluctuate in brightness, as their power supply becomes weak or inconsistent.
Battery issues are another major symptom. Your alternator charges up your battery while your car is on the move. If it’s not working, your battery’s power will quickly drain. This will lead to trouble starting your engine, stalling while driving - or a completely dead battery. So, keep an eye on your battery warning light, and don’t ignore it if it comes on.
If electrically powered components such as the windows, wipers, ECU, radio, and locks start to malfunction, this is a telltale sign of a failing alternator. You may also smell burning or hear grinding noises if the alternator itself starts overheating - or its components break.
Knowing what to look and listen out for is key here. Fixing your faulty alternator before it damages other parts of your car could help you avoid an eye-watering repair bill.
Electrical components rely on a steady input of power - and any fluctuations can cause them to stop working, meaning extra repairs and costs for you. It’s also best to get your alternator replaced before it fails completely. After all, if your alternator doesn’t work, your car may not either.
You could be left without any power to your engine, lights, doors, dashboard, or anything else, which could be incredibly dangerous if you’re on the move, especially on a busy road or motorway – and even more so at night.
Alternator replacement costs factors
How much it costs to replace an alternator in the UK depends on the following factors:
-
The make and model of your car.
-
Whether you choose original equipment manufacturer (OEM) or aftermarket parts.
-
How many electrically powered components your car has.
-
Local labour costs: Garages in big cities such as London often charge more than those in smaller towns or rural areas.
Alternator replacement costs can vary from as little as £100, up to around £800 for some higher-performance cars.
Alternator replacement costs by manufacturer
Here are some average replacement costs for some of the most popular car manufacturers on the UK market:
- Audi: £381
- BMW: £393
- Citroen: £415
- Ford: £313
- Honda: £387
- Hyundai: £336
- Kia: £370
- Land Rover: £400
- Mercedes-Benz: £461
- Nissan: £350
- Peugeot: £385
- Renault: £416
- Toyota: £316
- Vauxhall: £320
- Volkswagen: £318
How long does an alternator last?
An alternator is designed to last approximately 100,000 to 150,000 miles. However, certain factors can influence how long yours will last:
-
Driving style - Stop-start driving - and frequent, fast acceleration can put a strain on your alternator.
-
Overuse of electric and electronic systems - Constantly using electrically powered systems such as the air conditioning, heated seats, and entertainment systems may shorten the lifespan of your alternator.
-
Mileage and wear - The further you drive, the more wear and tear your alternator will experience.
-
Maintenance - Make sure you keep up with your car’s servicing and maintenance schedule – and take your car to a mechanic if you spot any of the warning signs we highlighted earlier. If your car is poorly maintained, it is much more likely to develop an alternator fault.
DIY vs. professional alternator replacement
Replacing an alternator is a complex task, requiring specialised mechanical knowledge and equipment, such as a tensioner tool, multimeter, and a battery terminal puller.
Unless you have the required skills, tools and experience, this is best left to a qualified mechanic. If you have work carried out at a professional garage, this is usually covered by a warranty. However, if you attempt alternator replacement yourself and make a mistake during the process, you risk seriously damaging your car - and facing a hefty repair bill.
Nevertheless, if you’re confident in your abilities, you could potentially save some money by taking the DIY route, as you’ll only have to pay for the part itself.
Can you drive a car with a faulty alternator?
Whilst it is possible to drive a car with a faulty alternator, it’s not advisable to do so. You’ll risk breaking down, damaging the other electrical components in your car, and having to replace your battery.
So, if you discover or suspect an alternator fault, take your car to a garage as soon as possible.
How long does it take to replace an alternator?
Generally speaking, it takes around one to two hours to replace an alternator. However, this does depend on the make and model of your car, whether any other damage needs to be addressed - and the speed and skill of your mechanic.
Is it worth replacing an alternator?
The alternator plays a crucial role in keeping your car running smoothly and safely, so it is absolutely worth replacing if you’re going to continue to drive your car.
If you’re deciding whether to repair or sell your car, it’s worth knowing that replacing your alternator is likely to increase your car’s market value.
Related cost guides
- How much does it cost to replace your head gasket?
- How much does it cost to replace a car battery?
- How much does it cost to replace your gearbox?
- How much does it cost to replace your car door?
- How much does it cost to replace your exhaust system?
- How much does it cost to replace your clutch?
- How much does it cost to replace your car radiator?
- How much does it cost to replace your cambelt?
- How much does it cost to replace brake pads?
- How much does it cost to replace your headlight?
- How much does it cost to replace car suspension?
- What are the most expensive car parts to replace?
- How much does it cost to replace a windscreen?