Why Is My Car Making a Grinding Noise?

Ellie Dyer-Brown, 3 months ago

5 min read

  • Diagnostic
Grinding noise blog

WhoCanFixMyCar explains why your car might be making a grinding noise and what you can do to fix it.

Sometimes, cars seem to have a language of their own. Understanding the meaning behind the unusual noises they make can help you diagnose problems early. This guide focuses on the most common causes of grinding noises.

Contents

1. Water pump

2. Alternator

3. Air conditioning compressor

4. Clutch

5. Wheel bearing

6. CV joint

7. Brake pads


1. Damaged water pump

If the sound isn’t coming from your brakes and happens while the engine is running, you may have a problem with your water pump. Grinding noises from the water pump usually indicate worn bearings.

Water pump image

While it’s possible to replace the bearings, the seals will likely be worn, too, so the whole water pump is usually replaced as a precaution. You shouldn't put this repair off - a faulty water pump could cause your engine to overheat, resulting in more damage and an expensive repair bill.

How much does it cost to fix a damaged water pump?

The current average price for a replacement water pump across all makes and models on WhoCanFixMyCar is £272.67.


2. Worn alternator

The alternator charges the battery and provides the vehicle with electrical power while the engine runs. As it ages, the bearings inside the alternator wear out, and the pulley becomes slack enough to move side to side while spinning. This movement causes a grinding noise.

Here are five signs of a faulty alternator.

A car alternator.

How much does it cost to fix a worn alternator?

While alternators can be expensive to replace, it is a relatively easy job to complete, which will reduce labour costs.

Car MakeAverage Price
Audi£540.88
BMW£504.91
Citroen£501.42
Ford£386.55
MINI£446.33
Mercedes£563.22
Nissan£426.88
Peugeot£518.55
Renault£486.12
Toyota£383.24
Vauxhall£401.03
Volkswagen£414.84
Volvo£427.07

3. Air conditioning compressors

If you only hear a grinding sound when your AC is on, this indicates a problem with the compressor. The compressor sends refrigerant through the air conditioner’s lines and allows a heat exchange.

Find out what else can go wrong with your aircon.

The pistons often make an unpleasant grinding sound when the compressor wears down. Getting your AC repaired isn’t urgent, as it won’t affect the overall functionality of your car. However, you should consider booking a replacement if summer is approaching.

How much does it cost to fix your aircon?

The first step is accurately diagnosing the problem with the aircon system, which is done during an aircon service. The average price when you book through WhoCanFixMyCar is £94.72.


4. Worn clutch

A grinding sound that happens when you change gears indicates a problem with your clutch.

A mechanic holding clutch components in front of engine

Simply put, the clutch's purpose is to separate the engine from the wheels, allowing you to change gears. It consists of the clutch plate, pressure plate and flywheel. This guide discusses how long a clutch lasts.

If there is a problem with one or all of these components, you’re likely to experience several symptoms in addition to a grinding noise:

  • Squeaking or grumbling sound when pressed.

  • Difficulty changing gear.

  • Slipping clutch, resulting in a brief loss of acceleration.

  • Spongy, sticking or vibrating clutch pedal.

Clutch repairs have a reputation for being expensive, but the cost depends on the nature of the problem and your car's make/model. If you suspect your clutch might need repairing or replacing, take your vehicle to a garage as soon as possible to avoid causing more damage.

Discover what happens when your clutch is replaced in this guide.

How much does it cost to fix a worn clutch?

A clutch replacement costs £624.59 on average when you book through WhoCanFixMyCar.


5. Worn wheel bearing

Have you noticed a grinding noise when you turn? If so, a worn wheel bearing is probably the culprit.

Wheel bearing image

A bad wheel bearing may emit a quiet grinding sound all the time, speeding up and slowing down as you do, but the noise often becomes more noticeable when you turn. Other symptoms include uneven tyre wear, ABS failure, and the vehicle pulling to one side.

You shouldn't ignore signs of a bad wheel bearing because when it fails, the affected wheel will stop working and may even fall off - which is particularly dangerous if you're driving at speed when it happens.

How much does it cost to fix a worn wheel bearing?

A wheel bearing replacement costs £257.63 on average when you book through WhoCanFixMyCar.


6. Worn CV joint

Constant velocity (CV) joints are located at each end of the drive shaft, connecting the wheels to the axle and transmission. They shift torque to the wheels at a controlled speed and are responsible for the up and down motion of the suspension system.

CV joint

When a CV joint starts to fail, you'll likely notice your car pulling to one side due to a wheel losing power, and this movement may also be accompanied by a grinding, ticking or clicking noise. You shouldn't drive with a damaged CV joint because it is dangerous and will cause further damage.

How much does it cost to fix a worn CV joint?

The average price of a CV joint repair is £171.87, according to our data.


7. Worn brake pads

Gringing when you apply the brakes is most likely due to worn brake pads. However, typically, it happens at a later stage of brake wear and is preceded by a high-pitched squeaking or squealing sound.

Car brakes replacement.

The grinding noise is caused by the metal backing plate clamping onto the disc instead of the pad, which is worn away. Learn more about how brakes work in this guide.

It's always best to fix brake problems as soon as you notice them because the longer you leave them, the more expensive the repair is likely to be.

How much does it cost to fix worn brake pads?

Brake repairs cost £440.93 on average when you book through WhoCanFixMyCar.


If you have any other issues with your car that you'd like to try to diagnose yourself, check out our guide on self-diagnosing car problems. The more you know about how your car works, the better.

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