Alternator Replacement Cost: UK Prices Explained

How Much Does An Alternator Replacement Cost?

The cost of an alternator replacement can vary depending on the car you drive. Larger models, or more premium brands like BMW or Mercedes cars, can cost upwards of £800. Average alternator replacement price in 2025 was reported by the RAC as £458 with brands such as Ford, Vauxhall and Toyota all coming in very close to that valuation.

Around half of the fee will pay for the part itself, while the other half will cover labour costs. The replacement job typically takes no more than three hours. The model of car you’re asking the mechanic to work on will impact how long it takes, with some alternators being positioned in harder-to-reach spots within the engine bay.

What Pushes The Price Up?

The make and model of your vehicle can have a significant effect on how much a new alternator will cost you. More premium car manufacturers will be more expensive for repairs; their parts carry the premium price tag that comes with the badge, and are usually more technologically advanced, especially when electronics are involved.

The time it will take to complete the job will also increase the price, but this would be because you’re paying for more labour rather than a more expensive alternator. Cars with simpler, less compact engine bays will be faster to work on and cost less overall.

New, Remanufactured Or Used Alternators

OEM & Aftermarket Units

OEM stands for Original Equipment Manufacturer and refers to parts that are designed and built by the original manufacturer and to their exact specifications. An OEM alternator will cost you more than an aftermarket part would, but you’ll know that it’s the exact one that was meant to be fitted in your vehicle. This means it will fit inside your engine bay perfectly and it will run just as it’s meant to, with no disagreement from other parts of the vehicle.

Aftermarket parts are a completely viable option but some will be better than others. As with most things, the cheaper you go, the less reliable it’s likely to be. There’s also the possibility that they won’t properly fit your car because they’re not made to the exact precise specs as OEM. In worse-case scenarios, this goes beyond the alternator alone. It could end up damaging other parts of your car, such as the electrics, and costing you more in the long run as you pay for extra repairs.

Remanufactured & Reconditioned Units

Buying an alternator that’s been used previously is a good budget-friendly option when replacing one. Remanufactured or reconditioned units will have been cleaned up and tested (with failed components replaced) to get them as close to ‘new’ as possible.

These parts will be much cheaper, but their reliability should still be close to that of a new part. Just make sure you buy remanufactured or reconditioned parts from a reputable seller to ensure you’re getting the best quality on the second-hand market.

Second-hand Parts From Breakers

Breaker yards (or salvage yards) will strip down old cars that aren’t ready to be totally scrapped and remove any parts that are still in working order. This can include alternators. Buying an alternator from a breaker can be an excellent way of getting a bargain, but you should know a little bit more about what you’re looking for.

The condition of these alternators might not be top-notch, and they might not always work perfectly. Good salvage dealers will test their parts before putting them up for sale, so you should always check to see if this is the case where you’re thinking of buying from.

Online shopping has made it much easier to buy second-hand parts from breaker yards. These days, they catalogue their stock online and you can even search by your vehicle make & model to ensure the alternator you purchase will fit your car.

Exchange Surcharges

When you need your alternator replaced, you’ll also have to get rid of the old one. Many parts vendors will take the old one off your hands so that they can refurbish it for resale. However, they will typically charge you extra when you buy the new part. That extra fee will then be refunded to you once they receive the old part.

Extra Costs To Budget For

Unless you know for sure that the alternator is the problem, there might be some other costs involved in fixing this problem:

Charging System Diagnostics

Diagnosing a problem in your car isn’t a complicated process, nor does it take too long. In most cases an on-board diagnostics (OBD) kit will do the job. For problems with the charging system though, a multimeter is likely to be the better option. The garage you take your car to will know how to diagnose the problem properly using the correct kit. The cost of a diagnostics test will sit somewhere in the range of £50 to £100.

Drive Belt and Tensioner

These parts work in tandem to transfer power between the car’s engine and the alternator. So, even if your alternator is working, it’ll count for nothing if your drive belt and tensioner also need replacing. You should budget for these added part replacements, just in case.

Depending on make and model, these parts could cost £40 to £180 on top of the charge for a new alternator.

Battery Replacement and Registration

If your battery is also on the way out, it might be recommended that you replace it as well as the alternator. These replacements can also vary in price depending on the type of battery you want or need, but the standard variety will cost between £40 and £120. Installation will then set you back another £40 or so, plus you’ll need to properly dispose of the old battery which, due to the hazardous nature of the battery acid, requires another paid service. However, some businesses will roll this cost into your quoted price. Check whether disposal is included when you get a quote. Disposing of batteries yourself can be quite a hassle to carry out.

Next up once the new battery is fitted and the old one is disposed of, you should register your replacement battery. This tells your car’s ECU (Electronic Control Unit) that a new battery has been installed.

Some modern vehicles are clever enough to charge your car based on the lifespan of the battery that’s installed. As car batteries get older, they will lose their maximum charge, not too dissimilar to the battery life and performance of your mobile phone.

If your car thinks you’re still using an old, worn-out battery, it could charge it for longer to compensate. So, if you then replace the battery with a new one but don’t register it (to tell the vehicle you’ve swapped it) the ECU could then overcharge the new battery and damage that one too.

Hybrids And Electric Cars

Hybrids and electric vehicles don’t have traditional alternators with a belt and tensioner system. Instead, they use internal generators or converters to power the 12V battery under the bonnet. EVs will take power directly from their massive main battery to charge their traditional 12-volt, using a DC-to-DC converter to do so. They will also harness the power of regenerative braking to store energy in generators, which can then be sent back to the main battery, keeping the 12V battery fairly self-sustainable.

Mild hybrids do work slightly differently. These vehicles never fully rely on electric power to keep them moving, so without a working petrol or diesel engine, they’re going nowhere. That combustion engine still requires a standard alternator. Some of these models use a 48-volt alternator in place of the standard 12-volt alternator. As these parts handle much more demanding power levels, they usually come at a higher price point.

Signs Your Alternator Is Failing

Look out for issues related to electric power to identify a failing alternator. First and foremost, you might get a battery-shaped light appear on the dashboard. If you’re not yet at that stage, other signs include dimming headlights or electric windows not operating properly. The most troublesome sign of all is the flat battery. If your car keeps failing to start or stalls when it shouldn’t, your alternator could be to blame.

Away from electrical symptoms, you might hear a grinding or squealing noise when the car is running, which gets louder when the air conditioner or radio is on. This could even be followed by a burning smell. These are all signs of physical wear to the alternator or the belt, rather than simply a lack of power.

Is It The Alternator Or The Battery?

So how do you determine which part needs replacing? It can be tricky, as they’re both directly linked to the electrical system within the vehicle.

If you notice an unpleasant eggy smell, the battery is likely at fault. This would occur when battery acid (which is sulphuric) is leaking. This is a big problem and should be dealt with as soon as possible. As we mentioned above, a faulty alternator might make a horrible squealing noise or smell of burning, but it should be distinguishable from the leaky battery smell.

There is a way to try and identify the difference yourself, but it’s not 100% guaranteed to be correct, so you should leave it to the professionals if you’re unsure. If the car cuts out while it’s running, it’s probably the alternator, but if the car won’t start at all, it’s more likely to be the battery. The reason being that the alternator’s job is to keep that battery charged. If it won’t kick into life at all then the battery is probably dead. If it’s got a little bit of power, the alternator is probably not working as it should and the battery is running out of charge and not being replenished.

Can An Alternator Be Repaired?

Yes, an alternator can be repaired, and doing so could save you a lot of money compared with simply buying a new replacement part.

Alternator repairs involve taking it apart and replacing the individual components that are broken, like the rotor or rectifier. Once these are replaced, the alternator should work as normal again and can be put back together and refitted into the vehicle.

How Long Does The Alternator Replacement Job Take?

Luckily, alternators in cars are usually pretty easy to access, so the job could take around an hour at a professional garage. That being said, vehicles with more complicated layouts under the bonnet could take a couple of hours longer because other components might need to be removed to gain access.

Replacing An Alternator Yourself

If you’re considering doing this job yourself, give yourself plenty of extra time. You’re working with electricity and acid-containing batteries. The potential dangers are quite serious, so you don’t want to rush things – and you shouldn’t go down the DIY route if you’re not feeling up to it.

If you do decide to carry out the replacement yourself, here’s a step-by-step guide on how to do so:

1. Remove the belt – The belt should be kept to one side, and you may as well inspect it for any signs of wear (like cracking) while it’s off, too.
2. Disconnect the battery & other electrical connections – There’s likely to be a main connector and a small plug, both of which will need to be carefully disconnected.
3. Unbolt the alternator – The existing part will be connected with bolts that’ll need to be unfastened. Keep the bolts somewhere safe so you don’t misplace them.
4. Double-check you’ve got the right part – Installing the wrong alternator could do further damage to your vehicle, so take a second to confirm your replacement is correct.
5. Bolt on and reconnect – Reverse the process with the new part, securing it with bolts before reconnecting the electrics.

Getting A Fair Quote

The best way to ensure you’re quoted a fair price for your alternator replacement is to shop around and compare prices. Certain websites can compare these prices for you and let you book in with the cheapest directly, but it also helps to understand the rough estimate cost of this work before you go looking for a mechanic to do the job.

Is It Worth Replacing The Alternator?

Repair Cost Against Car Value

With any car repair work, it’s important to check the price ahead of time. This allows you to weigh up whether it’s financially worthwhile even getting the work done!

If your car is old or has a lot of miles on the clock, you could consider scrapping it, especially if a broken alternator seems to be one of a never-ending list of issues you’re constantly having to deal with.

When Selling Or Scrapping Makes Sense

Generally, if the repairs are starting to add up to more than the value of the car itself, it is probably time to scrap it and get something more reliable. You could also try to sell it to somebody who will replace the part themselves, but you should disclose the issue to any potential buyer. You should also take into account the effect this could have on the price buyers are prepared to pay.. 

Selling A Car With A Faulty Alternator

It is possible to sell a car with a faulty alternator. You’ll have a couple of options. You can sell it as salvage to a salvage dealer – Scrap Car Comparison can get you a quote for that in seconds, with free collection included.

Alternatively, you can sell it privately, but you will need to be completely open about the problems the car has. You should lower the price accordingly, but even still, you may not have too much interest from prospective buyers. Most people in the market for a new car want something they can drive away immediately, not something they’ll have to repair – even if it is a bargain.

Scrapping A Car With Alternator Failure

If you’ve decided it is time to scrap your car, here’s what you need to know next.

Authorised Treatment Facilities & Certificates Of Destruction

The end-of-life vehicle industry is heavily regulated these days to let drivers scrap or sell their cars as salvage with peace-of-mind. You should always scrap with an Authorised Treatment Facility (ATF). These scrapyards work to all legal standards and have been approved by the relevant authorities. Scrap Car Comparison partners with ATFs all around the UK, so you know you’re in safe hands when you scrap with us.

A Certificate of Destruction (CoD) is a document that acts as proof when a vehicle has been scrapped. You can request a CoD when your car has been disposed of to keep on record yourself. This way, if there are any future issues with the DVLA you have definitive proof that the car has been destroyed.

Telling DVLA And Handling The V5C

It’s crucial that the DVLA is told that your car has been scrapped and that you are no longer the registered keeper. This is because any correspondence – including speeding fines or other similar notices and tax fines – will still be linked to you if you fail to do so. Failure to inform the DVLA of your vehicle’s scrappage could even result in a £1,000 fine.

There are also a few steps that must be followed involving your V5C logbook when scrapping your car. Your ATF collector will be able to help you with these, but we’ll outline what needs to be done as well. You will need to remove and fill in the yellow part of the logbook, titled “sell, transfer or part-exchange your vehicle to the motor trade,” and keep it yourself. The rest of the V5C should be handed over to the vehicle collector. It’s that yellow slip that you can use to notify the DVLA of the sale.

Road Tax Refunds And Private Plates

Getting a refund on your car tax is very simple. Once you’ve notified the DVLA that the car has been scrapped, they will process your refund automatically and send it to you via cheque. This takes 4 to 6 weeks. You will only be refunded for any full months of tax left, not partial months, even if you’ve only ‘used’ one single day.

Private plates can be saved when scrapping a car, but this will also have to be done via the DVLA. You will need to place the registration number on retention to prevent it from being lost when the car is disposed of, or transfer it to a new vehicle. You can keep the plate on retention for 10 years before you need to renew your right to the registration again.

Checking A Buyer Is Licensed

The most straightforward way of confirming that an ATF is licensed is to check the Environmental Agency Public Registers Online (in England), the Scottish Environment Protection Agency, Natural Resources Wales or the Department for Agriculture, Environment and Rural Affairs (in Northern Ireland). If they’re not on the list, they’re not a fully-authorised treatment facility.

Another check you can make is to ask the ATF if they’ll provide you with a Certificate of Destruction once your car is scrapped. If they say no, they are not genuine.

Cash Payment Rule By Nation

If you’re in Northern Ireland, you can be paid in cash when you scrap your car. However, if you’re in England, Scotland or Wales cash payments for scrap or salvage vehicles were made illegal with the introduction of the Scrap Metal Dealers Act in 2013. This was to crack down on stolen vehicles being sold and scrapped without a digital trace of where they ended up.

FAQs

Can I drive with a bad alternator?

You will only be able to drive your car until the battery runs out, which is likely to be no longer than an hour. Your alternator keeps the battery charged while the vehicle is running, so without it, that power isn’t being replenished. It is not advisable to drive knowing you have a bad alternator.

Is a faulty alternator an MOT failure?

Your alternator won’t directly be an MOT failure, but it can certainly lead to a fail in many other ways. If the car won’t start, or stalls repeatedly, the car will fail. Similarly, if the battery light is illuminated on the dashboard, it will fail. As well as this, if vital electrical components don’t operate properly due to a lack of power, the car will also fail.

How long does an alternator last?

The average lifespan of a car alternator is between 80,000 to 150,000 miles. Higher electrical loads, like if you’re using a powerful aftermarket sound system or if your battery is struggling to retain its own power, will put added strain on the alternator and reduce its overall lifespan.

Should I replace the battery when I replace the alternator?

No, you don’t need to replace the battery and alternator at the same time unless they are both faulty. If a problem can be accurately identified with just one part, only replace that part.

What does an alternator do in a car?

The alternator in your vehicle generates the power to charge the battery. That battery then operates the electrical systems, like your radio, headlights and electric windows. If the alternator isn’t working, your battery will simply use its power up and not be replenished. You can find out more about how the alternator works, but at the end of the day, it’s all about creating power.

Can an alternator be fixed at the roadside?

Roadside assistance can, in some cases, make minor repairs to electrical systems or charge your car enough to get you moving again. What they can’t do, however, is replace an alternator at the roadside. This job is a bit too complicated to be done in such an environment, especially when you consider the dangers of passing traffic and complications from bad weather.

References:

• https://www.protyre.co.uk/car-help-advice/how-to/how-can-you-know-if-it-s-a-dead-battery-or-alternator
• https://www.gsfcarparts.com/knowledge-hub/alternator-replacement-a-uk-diy-guide