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Alternator Replacement
Typical Cost: Medium
Mobile Repair? Yes
Typical Lead Time: 2 - 24 hours depending on part availability
What does an alternator do?
The alternator is an electrical generator driven by a belt from on the engine to charge the battery of the car. It is vital that the alternator works effectively as once the engine is running the power it produces provides the electricity to a range of components.
How does an alternator work and what are the components?
The alternator is a generator that is turned by a belt from the engine crankshaft pulley. The rotating electromagnet inside the unit creates an alternating current (AC), that is converted to direct current (DC) by the rectifier. The regulator then controls the amount of the power generated in line with demand to recharge the battery.
The charging system warning light is used to “excite” or wake up the generator and start distributing the power being created. This is why the battery light comes on with the ignition, then goes out once the charging is in operation - if the battery light remains on, or comes on with the engine running then there is an issue with the alternator generating power and the battery will not be recharged.
Typical symptoms that require an alternator to be replaced.
- When the battery warning light on the car's dashboard has lit up.
- Various electrical controlled functions shut down whilst you are driving (e.g. ABS/ESP/SRS).
- When the battery has not been charged after a journey.
What happens during an alternator replacement?
Changing an alternator is a routine repair for all mechanics and can be done both kerbside as well as in the workshop, providing it is safe to do so. Due to the disconnection of the old battery and the connection of the new one, your radio code may be lost. It is important that you have this to hand and give it to the mechanic should they need to input the code into the radio in order for it to work.
Whilst there are variations between manufacturers, the basics are pretty similar.
The mechanic will;
- Physically inspect the car's battery charging system.
- Inspect the alternator's drive belt
- Test the voltage output of the alternator at the battery terminals.
- Isolate the battery (usually by removing the negative terminal)
- If appropriate, continue on to replacing the alternator.
- If required, update the vehicle's electrical system to accept the new alternator.
- Start the engine and retest the charging system
- Enter the radio code if required and present,
- Check the operation of the electric windows if fitted.
- Test drive the vehicle.
What does this repair cover?
Unless otherwise stated, the quote for your brake pads to be replaced will cover;
- The alternator (of the same rating recommended by the manufacturer)
- Coming to you
- Fitting of the alternator
- Coding of the alternator to the vehicle's electrical system (if required)
- Entering the radio code if required and present
- Ensuring the electric windows close and open as they should
- Checking that that charging system is working appropriately
- VAT (if applicable)
- 12 months parts and labour warranty
Please note that in most cases the mechanic will need to take the old alternator and return it to have the surcharge on the new one reimbursed. Should you wish to keep the old alternator, there may be an additional charge to do so.
What to search for on the ClickMechanic site?
Alternator replacement
How much does it cost to have an alternator replaced?
The cost of an alternator replacement depends on your car and what parts your car's manufacturer recommends.
Find out what you could save by visiting ClickMechanic
https://www.clickmechanic.com/jobs/alternator-repair
FAQ’s
Can my existing alternator be repaired?
Whilst it is theoretically possible to do, it would actually work out to be more expensive. Internal alternator parts are not “off the shelf” and would require ordering in and along with the strip down, cleaning and rebuild time, the labour costs would push this above the price of the new alternator. It could also mean that you would be without use of the vehicle for some time. It just isn’t worth it, so we do not carry it out.
Can a second hand alternator be fitted?
As our work carries a 12 month parts and labour warranty, we will not fit second hand parts, especially as we do not know it’s internal condition and likelihood therefore of failure.
Is the quote the final price I will pay?
Unfortunately, with alternators, even the dealership cannot be 100% certain what has been fitted to the car until they actually see the unit. One of the reasons for this is that when ordered from new, there are usually a vast range of additional extras that are available. Some of these extra’s require the vehicle to be built with higher (or even lower!) rating alternators. Optional extras such as heated and electrically adjusted seats for example mean a much higher rating of alternator would have been fitted.
ClickMechanic price the part on the most widely used version, if your vehicle doesn not have this fitted, then an additional charge may be required. However, in this scenario, the both the mechanic and ClickMechanic will discuss this and the options prior to commencing the actual replacement.
Can I supply my own parts?
No, we will not fit customer supplied parts unless they are a brand new item, purchased from a dealership with the receipt as proof of purchase. There is no flexibility over this due to insurance and warranty issues.
What happens if the mechanic finds that the alternator doesn’t require changing and the problem is due to another issue?
In this scenario, the mechanic will provide a no obligation quote for the correct repair. Should you accept this, the mechanic can alter the booking accordingly. If you decide not to go ahead with the alternative repair, the mechanic can change the booking to a call out and diagnostic booking and charge according to the time spent with the vehicle and call out.
Associated repairs
Battery replacement (Vehicles with stop/start)
Battery replacement (Vehicles without stop/start)
Starter motor replacement
Battery warning light inspection
Battery drain investigation