Alternator repair & replacement made easy

The alternator is an electrical generator driven by a belt off the engine to charge the battery of the car. It is vital that the alternator works effectively, seeing that the battery provides electricity to a range of components.

• Mechanic will inspect the car's battery charging system.
• Mechanic will inspect the alternator's ancillaries (drive belt, cables etc.)
• Mechanic will test the voltage output of the alternator.
• If necessary, the mechanic will replace the alternator.
• Mechanic will advise if any other parts of the electric system need to be replaced.
• Mechanic will test the charging system and will test drive the car.

Unless you are a qualified mechanic with the required skills, training and equipment to do the job, we strongly recommend an alternator replacement is only carried out by a professional mechanic. ClickMechanic can help get you a vetted and local mechanic to carry out the work. Just enter your postcode and your car's registration number at the top of this page and select the work needed to get an instant fixed price up front.

• When the battery warning light on the car's dashboard has lit up.
• When the battery is not being recharged

On average, alternator replacement times can range from 1 hour to 2.5 hours with an average of just over 1 hour. The time that the job takes will depend on a number of factors, like your vehicle's make and model, year, as well as other factors. Select your car at the top of this page for information on job time and cost for your vehicle through ClickMechanic.

Generally alternators only need to be replaced if there is an issue with them. Should you experience any problems like those listed it is important to have the battery charging system inspected and, if necessary, have the alternator replaced.

As the demand for more and more electrical equipment and devices on modern vehicles increases, the demand on the alternator is increased. Therefore whilst the units themselves have improved dramatically in design and reliability, this is outweighed by the increased reliance on it. So, alternator replacement is a frequent repair on most vehicles at some point.

If the battery light remains on with the ignition (and does not go out once the charging is in operation), or comes on with the engine running then there is an issue with the alternator generating power and the battery will not be recharged. It is important to get a professional mechanic to check the issue as soon as possible.

Because it is not possible to turn the alternator off and it will therefore always be turning when the engine is running, there is little you can do to prevent wear and tear. Obviously as an electrical device, they do not like water, so avoiding flooding is important!

If you have a bad alternator then technically your car will likely still drive, but it is advisable to get help from a professional mechanic before running the vehicle again. Not addressing issues with the alternator will lead to your battery not getting charged and a flat battery, ultimately leading to your vehicle not being able to start again.

Whether you will need to replace the battery with the alternator ultimately depends on the battery's condition. If you're not sure if it needs replacing we'd recommend booking with a professional mechanic to check the issue and advise on next steps.

There are a number of factors that would determine how long a battery would last if the alternator is bad and not charging it correctly. Primarily it will depend on how much energy your car consumes and the condition of the battery.

No, a car will not fail its MOT on an alternator issue itself. The alternator is not checked as part of the MOT, but a garage may flag it as something to address outside of an MOT to help ensure your vehicle will be able to charge its battery as intended.

A bad alternator can damage a new battery if the battery is not receiving the proper charging voltage. While it may not completely destroy it, a faulty alternator can cause a new battery to drain more quickly than it should.

It is possible for a car to run without an alternator, but it will not run for very long. It is likely that the battery will eventually die, and the car will eventually come to a halt.

Alternators can fail suddenly, but more often than not they will slowly lose their ability to charge the battery and eventually die. So even if it fails while driving, you may still be able to drive the car a few miles before the car comes to a complete stop.

The easiest way to check if your alternator is working is to start the car and let it idle. Then, turn on all of the car's accessories one at a time. If the car's battery dies while the accessories are on, then the alternator is not working.

Additionally, the battery should be tested for voltage. If the battery is low, the alternator may not be charging the battery. Depending on the electrical system, a voltmeter reading in the 13.8 to 15.3 volt range with the engine running, lights and accessories off, generally indicates that the alternator is working as it should be.

If the battery is not dead, then yes, you can jumpstart a car with a bad alternator, but it will only run for a short period of time before the battery is drained again.

If your alternator dies while driving, your car will eventually lose power and come to a stop. You may notice the first signs of a dying alternator with dimmed interior lights and warning lights on the dashboard. The best thing to do in this case is find a safe place to stop and call for professional help.

In most cases the alternator would be replaced if it bad or faulty. Alternators can be refurbished but often getting a new one fitted is more cost-effective. An alternator is an electrical component that is key to supplying power to your car so fixing it is a job best left to qualified technicians.