What are the most expensive parts of a car to replace?

    Repairing broken or faulty parts in a car is an unexpected expense that we can all do without. But, knowing which car parts are the most expensive to replace can help you decide what, if any, money you should set aside for car repairs. 

    Maintaining your car as quickly, and to as high a standard, as possible will help to maintain its valuation. Since cars are many people’s highest-value assets, it’s worth treating them well so that when you’re ready to sell your car, you know you’ll get a good price.

    From the clutch to the alternator and the water pump, read on to learn the costs and considerations for these common replacement parts, and whether they are normally covered under warranty.

    What are the most expensive car parts to replace?

    You need to know you’re spending your money wisely when looking after your car, and this includes knowing which repairs are essential to make quickly, even if they leave you out of pocket.

    While your car is in warranty, normally all repairs and replacements to parts are covered. Standard wear and tear are sometimes not covered, so make sure you get any issues looked at quickly so you can prove you didn’t cause the damage through your normal driving habits.

    Engine parts

    an alternator inside a car

    Alternator repairs shouldn’t break the bank, however they are key to carry out as soon as you sense a problem.


    The alternator, a key component of the car’s charging system, converts engine energy into electrical power. It recharges the battery and fuels the electrical systems. Its complexity, quality materials, labor, and vehicle-specific design contribute to its cost. Ensuring smooth operation, it’s an essential, albeit relatively expensive, part of your vehicle.


    The Engine Control Unit (ECU) manages your car’s engine functions. It controls air-fuel mixture, ignition timing, and emissions. Its cost is influenced by advanced technology and vehicle-specific programming. Quality materials and intricate electronics contribute to its expense, but its vital role in optimizing engine performance justifies the cost.


    A radiator is a critical part of your car’s cooling system. It dissipates heat from the engine by circulating coolant through a network of tubes and fins. Its importance in preventing engine overheating and damage makes it relatively expensive. Quality materials, design complexity, and durability considerations drive up its cost. Without maintenance to your radiator, you could look at problems that categorise your car as a write-off.

    Head gasket

    The head gasket seals the engine’s cylinder head to the engine block. Replacing it can be relatively expensive due to the process of disassembling the engine. The head gasket plays a vital role in maintaining engine compression and preventing coolant and oil leaks.

    Dual mass flywheel

    The dual mass flywheel is a component in the car’s transmission system. It’s designed to reduce vibrations and enhance smooth gear changes in manual transmissions. Replacing it can be expensive due to often needing to remove the transmission. A worn or damaged dual mass flywheel can result in gearbox and drivability issues, justifying the cost of replacement.


    A turbocharger is an engine component that boosts power by compressing air entering the engine. Replacement costs can be substantial due to the precision engineering required and the need for high-temperature materials. Labour costs for installation can also add to the expense.

    Timing belt 

    The timing belt synchronises the engine’s camshaft and crankshaft, ensuring precise opening and closing of engine valves. Replacing it can be relatively costly due to labour-intensity, as it often requires engine disassembly. Moreover, the high-strength materials used for durability contribute to the price.

    Hybrid or electric battery 

    The hybrid or electric battery powers electric and hybrid vehicles. Replacing it can be one of the most expensive car repairs due to the advanced technology, the high-capacity lithium-ion cells, and intricate control systems. While costly, it’s a critical component that must be maintained to ensure the vehicle’s range and performance.

    Critical mechanical and safety parts

    someone with hands on the steering wheel
    Airbags have different locations in different car models, but are essential to maintain or replace as soon as you suspect there is an issue.


    The clutch is a crucial component in manual transmission cars. It connects the engine to the transmission, allowing the driver to engage or disengage power to the wheels. The cost of clutch replacement is influenced by the complexity of the manual transmission system, the labour-intensive installation, and the need for quality materials. Extensive wear and tear may necessitate a clutch replacement, making it relatively expensive.

    Automatic gearbox

    An automatic transmission simplifies driving by shifting gears without manual intervention. Replacing it is often a substantial expense due to the engineering, complex hydraulics, and electronics involved.

    Exhaust system 

    The exhaust system plays a critical role in vehicle performance and emissions control. Replacement costs can vary, influenced by the complexity of the components, materials used, and the level of customisation. Maintaining a properly functioning exhaust system is crucial for engine performance and compliance with emissions standards.

    Starter motor

    The starter motor is a crucial component in a car’s ignition system. It’s responsible for turning the engine over when you start the vehicle. The cost can be significant due to the intricate electrical components, labour required for installation, and potential need for quality materials. A malfunctioning starter motor can render your car immobile, justifying the expense of its replacement.


    Airbags are crucial safety features in cars, designed to protect passengers during accidents. You won’t pass your MOT without safe, working airbags. Replacing them can be expensive because of the specialized sensors, electronics, and deployment mechanisms. Malfunctioning airbags can result in a lack of crucial protection during collisions, making their replacement essential.

    Steering rack

    The steering rack is a vital part of the car’s steering system, responsible for translating the driver’s input into wheel movement. It can be relatively expensive to replace due to its detailed design, quality materials, and installation needs.

    Comfort and functionality parts

    a built in sat nav in a car showing directions
    If your in-car sat nav isn’t working, it may be more expensive to replace or repair it than to invest in another solution such as a phone mount or a non-integrated sat nav.

    Built-in sat nav

    Built-in satellite navigation systems provide in-car GPS for navigation. Costs can be high to repair or replace these due to the specific tech that is included in any given car model, and the need to integrate it with the rest of the vehicle’s electronics and controls.

    Air conditioning 

    An integral element of car comfort, the air conditioning system cools and dehumidifies the cabin air. Its cost is influenced by its intricate components, including the compressor, condenser, evaporator, and refrigerant. Repairs may range from minor issues like refrigerant leaks to more costly compressor replacements, making them potentially expensive to fix.

    How much does it cost to replace car parts outside of warranty?

    an exhaust on a red vehicle
    Your exhaust output will be monitored every time you get your MOT, and its efficiency is directly tied to your running costs. Investing in good maintenance and repairs is crucial.
    Car partAverage cost range (£)Labout cost (£)
    Alternator£350 – £800£100 – £450
    ECU£300 – £800£100 – £300
    Radiator£100 – £300£100 – £200
    Water pump£100 – £250£100 – £200
    Head gasket£300 – £800£300 – £500
    Dual mass flywheel£200 – £500£200 – £400
    Turbocharger£400 – £1,500£200 – £400
    Timing belt£200 – £500£150 – £300
    Hybrid or electric battery£1,000 – £5,000£300 – £800
    Clutch£300 – £800£300 – £500
    Automatic gearbox£1,000 – £3,000£300 – £600
    Exhaust system£100 – £500£100 – £200
    Starter motor£100 – £300£100 – £200
    Airbags£200 – £1,000£100 – £200
    Steering rack£400 – £1,000£200 – £400
    Built-in sat nav£100 – £500£100 – £200
    Air conditioning£300 – £800£150 – £300


    Which car has the most expensive parts?

    Luxury brands like Rolls-Royce, Bentley, and Bugatti typically have the most expensive car parts due to their unique designs and limited production. You may want to check the length and comprehensiveness of their warranties to avoid surprising maintenance costs.

    What is the most expensive part of a car engine?

    The most expensive part of a car engine is often the crankshaft. It requires precision engineering and high-quality materials for durability, contributing to its cost.

    Are OEM parts more expensive than aftermarket parts?

    OEM (Original Equipment Manufacturer) parts are often more expensive than aftermarket parts. OEM parts are produced by the car’s manufacturer and are designed to meet specific quality and performance standards.

    What are the most expensive car brands to maintain?

    Luxury and high-performance brands like BMW, Mercedes-Benz, and Porsche tend to be the most expensive to maintain due to the cost of specialised parts, complex systems, and higher labour rates at franchised dealerships.

    Choose the best time to sell your car

    If you’re not sure what your car’s value is to begin with, it’s hard to know what influence the cost of repairs, length of warranty, and other maintenance issues all have on the value increasing or decreasing.

    All vehicles depreciate at varying rates, with no rule of averages accurately describing any one car’s changing value. However, the health of your car parts has a big influence on what you can fetch for your car. 

    Motorway’s Car Value Tracker provides a free, reliable monthly price alert for up to six vehicles at once, so you can track your ongoing value and gauge whether the cost to repair your vehicle’s parts will be worth it for a healthy sale. 

    Follow the changes to your car’s value each month and choose the best time to sell, and make informed choices about investments in your car’s maintenance.

    Need to sell your car?

    Want to learn more about owning, maintaining, and selling your car? Check out more of our guides here, covering everything from Clean Air Zones to car tax, and plate changes to part exchange.