Alternator Replacement Cost

How Much Does an Alternator Replacement Cost?

If your car's got a faulty alternator, driving it much further than the end of your street becomes a problem.

Vehicles rely on electrical components - and since the alternator is responsible for delivering a lot of electrical power, your car's systems will fade out if it's not working as it should. At best this is inconvenient - but at worst, this could leave you stranded and unable to move your vehicle.

In this car alternator repair cost guide, we'll tell you everything you need to know about getting your alternator repaired or replaced - including how the alternator works, some signs of a bad alternator, and whether you can repair (rather than replace) an alternator.

We'll also explain exactly how to find a trustworthy mechanic in - and how to make sure you get the best price for the work that needs to be done.

How much does it cost to replace a car alternator?

There are a few variables when it comes to alternator replacement cost. Firstly, there's the type of alternator you need. Most car alternator prices will be around $150 - $300 - but if you've got a premium European vehicle (Audi, BMW, Mercedes, etc) you could be looking at a car alternator price around the $1,000 mark.

Then, there's the cost to replace an alternator. Some alternators are easy to get to - whereas others are more tricky. Labour costs will range between $200 - $700.

That means you're looking at a cost starting at around $350 - but could be more depending on your vehicle. Don't worry though - if you look for quotes through Auto Hero, you'll be able to access the best local mechanics near you, and pay significantly less than dealership prices.

What is an alternator and what does it do?

When most people think of the energy needed by a car, they think of the car battery. While it's true that the battery does provide power - that power is really designed for simply starting the car, instead of keeping everything powered up on your journey.

This is where an alternator comes in.

A vehicle's alternator turns mechanical energy into electrical energy. This energy is fed back into the car's charging system and is used to power all the electrical components we reply on - things like power windows, spark plugs, warning lights, power seats - and much more.

How does the alternator work?

A vehicle alternator is usually mounted on or near the engine block. This location is important - as the alternator is one of the components that the drive belt (sometimes known as a serpentine belt) has to be attached to.

As the engine runs, the drive belt is turned by the crankshaft pulley. This causes the belt to turn other components - most notably the car alternator and the air conditioning compressor.

As the belt turns, it causes a rotor inside the alternator to spin. Inside the rotor is an electromagnet (a long length of conductive wire wrapped around a piece of magnetic metal) - and when this has a voltage applied to it from the battery, it creates an electromagnetic field.

There's another part of the alternator that sits around the rotor. This is the 'stator' - another series of coiled wires.

If you listened hard in physics classes, you'll know that when a magnetic field is moved past this kind of coil, then voltage is created. Therefore, as the rotor spins (powered by the running car engine), this movement is turned into electrical energy - which is fed back into the electrical systems, keeping the battery charged and offering power to anything else that needs it.

In reality, an alternator is more complex than this - with additional components that are there to make sure the alternator output is usable. However, as a quick overview, you now have a rough picture of what the alternator's doing as you're driving to work.

Why might you need an alternator replaced?

As you can now tell, the alternator is an extremely complex part of the vehicle - with numerous delicate moving parts.

As with most electrical parts, frequent use (especially in a dirty and hot engine bay) will cause these parts to simply wear out. This often happens with the bearings that are at the heart of the alternator - helping the rotor and cooling fans spin. Bearings that are overly worn will collapse or seize, stopping the alternator turning.

Alternators sometimes also experience a break in one of the coils that create the electromagnetic field or the stator that sits around the rotor. There are also complex components called 'slip rings' that are an electric connection to the spinning assembly within the car alternator - and these can become burned out after prolonged use.

Charging issues are the most common issue with an alternator however. Undercharging or overcharging the battery can result from problems with the alternator and associated parts.

Is it possible to get an alternator repair?

Alternator repairs are possible - but having the one that comes off your car repaired isn't always the most cost effective way of getting back on the road.

An alternator repair usually isn't something a mechanic would carry out themselves. Instead, the broken alternator will be sent away and reconditioned. Rather than waiting for this process, the workshop may suggest sourcing a rebuilt alternator - one that has already been repaired and is supplied by a specialist retailer.

What are some signs of a failing alternator?

There are some solid warning signs to look out for that might suggest your alternator isn't in top condition. They include:

Dead battery - your vehicle won't start

The alternator doesn't provide the power to start your car - but it does charge the battery while it's running. Therefore, if the battery is low or flat when you switch your car off, it will also be flat when you go to switch it on again the following morning.

A dead battery doesn't always mean you need a new alternator - but it's one of the things a mechanic will check.

Strange noises from the engine bay

If the bearings within an alternator are failing, sticking, or have given up completely, then you can expect to hear strange noises as the alternator tries to turn.

Mechanical squealing, groaning, or other strange noises could be an indication that the alternator needs to be looked at.

Burning smell

Strange smell coming into the car or in the engine bay? If the alternator is severely overheating, you might notice a melting plastic or rubber smell.

Any burning smell from your car should be an indication to pull over and safely exit the car. Don't be tempted to lift the bonnet either as this can encourage burning - just let the car cool by itself. 

Electrical systems not working

Your car's alternator powers everything electrical in the vehicle - think windows, mirrors, stereo, electric seats, headlights, etc. If you notice that these aren't working as they should, it could be a sign that they're not getting enough power.

This fault is especially apparent at idle, when the alternator isn't working especially hard and could be showing signs of failing.

Engine warning light or battery light showing

Most modern cars have dashboards that light up like Christmas trees when you turn the ignition.

Most of the lights go out after a few seconds - but if you see any lingering, especially the 'check engine' light, battery warning light, or a light that says 'ALT' - it might be an indication that your alternator needs attention.

Car stalls or goes into 'limp mode'

Today, virtually all vehicles have electronic fuel injection systems - which, as you can tell from the name, require power to operate correctly.

If your alternator is having trouble delivering this power, your car may get the fuel it needs and stall - or, it may go into 'limp mode' (sometimes called 'limp home mode'). This is when the ECU recognises a significant error with the engine as will not allow the car move at more than around 40km/h or rev beyond around 2,000 RPM.

How is a new alternator fitted?

Let's take a look at how a mechanic near you would likely tackle an alternator replacement:

Inspection

The full charging system will be inspected and tested - including the battery's capacity levels and the alternator's output when the car is running.

Belt inspection

Faulty or damaged belts can sometimes stop a perfectly healthy alternator working as it should. As such, belts will be inspected to make sure they're operating the alternator correctly.

Battery disconnection

Next, the battery will be disconnected, so no power is running through the vehicle.

Alternator replaced

With the belts removed, the alternator can be unmounted fairly easily and a reconditioned or OEM alternator will be put back in its place.

Reconnect

With the new alternator installed and the belts replaced, the battery can be reconnected.

Alternator testing

The car will be started and road tested - with the electrical output of the alternator measured to make sure it's working as required.

Looking to get an idea of an alternator replacement cost ?

Don't worry - we realise there's a lot of technical information here about car alternators - but you don't have to be an expert to get an exceptional price for any work your alternator might need in .

If you've experienced any of the above warning signs and would like to get an idea of an alternator replacement cost, we're here to help. Give us some details about your car, your location, and the work that might need to be done - and we'll connect you with the best workshops in your area.

When we do, you'll be able to compare costs and read real customer reviews, so you can choose the one that's most suited to you.