Reasons Why You Hear a Knocking Sound Under Your Car While Driving (Solved)


Reasons Why You Hear a Knocking Sound Under Your Car While Driving

Reasons Why You Hear a Knocking Sound Under Your Car While Driving

Reasons Why You Hear a Knocking Sound Under Your Car While Driving
Reasons Why You Hear a Knocking Sound Under Your Car While Driving

Being a car owner is a fun thing, but it can be stressful sometimes that it makes you forget all the many advantages of owning a car. This is because of the fault that cars develop. It ranges from waking up to a flat tire to your engine not cranking. Whichever fault it is, there is always a solution for it.

Nobody wants to hear their car make a knocking sound from underneath. Apart from being scary, nobody loves the sound of a debit. Of course, when your car has a fault, you are sure to spend some money.

If you hear a knocking sound in your car and wonder what it could be, you are at the right place. We have put together all the possible causes of a knocking sound in your car.

Reasons you hear a knocking sound under your car

Some of the reasons that make your car have a knocking sound are:

  1. Tires that are not properly aligned
  2. Faulty belts
  3. Spoilt axles
  4. Broken ball joint
  5. Faulty brakes
  6. Worn wheel bearing
  7. Loose lug nut

1. Tires Not Properly Aligned

One of the causes of knocking sounds is when your tires are not balanced and properly aligned. It ruins the smooth driving experience and can damage your car. If you have a misaligned wheel or one of the parts in your tire is broken, you will notice a sound that occurs when driving. This sound happens when the affected tire rotates while driving and keeps on hitting the road.

Causes of misaligned tires

Any of the following reasons can cause misaligned tires:

  1. Potholes and uneven roads – as cars move through uneven roads and potholes, they suffer several vibrations on the wheels and tires. This is one of the causes of misaligned tires.
  2. Friction on roads – friction causes wear and tear, which is why tires become uneven and misaligned.

Effects of having a misaligned tire

  1. Constant vibrations from beneath your car. You can feel this vibration from the steering wheel
  2. You may begin to feel your car tilt to one end while driving
  3. Knocking sounds coming from the car – this happens when the tire rotates while you are driving. The affected part hits the road, and you hear a knocking sound.
  4. If your wheels are not properly aligned, then you should get it done by an experienced mechanic.

2. Faulty belts

When you have a faulty belt, your car will make knocking sounds. When the belt tensioner is not keeping it tight enough, it becomes loose and starts to hit different parts of the timing cover and its inside. This is what causes the knocking sound you hear from your car. You should get a mechanic to fix the belt when you observe this to avoid damaging other parts of your car.

3. Spoilt axles

Spoilt axles are one of the reasons you will hear a noise beneath your car while driving. A car axle is a shaft that is used to rotate wheels and gears. The axle is either fixed to the wheel or fixed to the vehicle. When the axle gets bad, it begins to make a sound when you are steering the car. When you make tight turns, the noise becomes louder. Axles are necessary for the movement of your car, and A bad axle is dangerous. If you observe any sound coming from your car axle, you should get it checked and fixed as quickly as possible.

4. Broken ball joints

A bad ball joint is one of the reasons you might be experiencing knocking sounds from your car. Ball joints are bearings used to connect your vehicle’s control arms to the steering knuckles. It is called a ball joint because it resembles the ball and socket joint in the human body. A broken ball joint makes a clunking sound that comes out from one side of the vehicle. A bad ball joint can cause your car to vibrate at the front. This can make your car completely fail if it is not attended to.

Signs of a Bad Ball Joint

Some of the signs of a bad ball joint are

  • Vibration from the car which is noticed at the front area of your car
  • Tires begin to wear out quicker than they should
  • The steering is not steady. It begins to move in one direction

If you observe a sound from your car that makes you feel you have a bad ball bearing, then you should think of taking it to the mechanic for a search and repair.

5. Faulty Brakes

Brakes are delicate parts of your car and can be faulty at any time. When the bolts of your brake or calipers are loose, then you are likely to hear a knocking sound when you apply your foot on the brakes. This can also be an indication that your shock absorber needs to be changed. The brake is very important, and you should fix any fault related to the brake immediately. Once you notice this problem, you should not hesitate to take your car for a mechanical diagnosis. You can also replace the shock absorber if it’s bad to be on the safe side.

6. Worn Wheel Bearing

A worn wheel bearing can cause a lot of noise when it has gone bad. The wheel bearing is responsible for connecting the wheel and the axle of your car. It allows the wheel to rotate without friction. When worn out, the wheels are not able to rotate freely. This causes a knocking sound on your car. You should replace the wheel bearing immediately you notice a problem.

7. Loose Lug Nut

A lug nut is used to fasten and secure a wheel on your car. The lug nut sometimes gets loose and might even go out. When this happens, you begin to hear a sound coming out from that part of the car. Loose lug nuts can bring other problems outside the knocking sound. You should always check your tires to make sure the lock nuts are properly screwed and tightened.

8. Bad Bushings

I believe you must have been heard your mechanic mention the ord bushing a few times. The bushing is responsible for helping maintain the alignment of your car. They help to balance the suspension and wheels. Bushings wear out after a period of driving your car regularly. When they break, you begin to hear knocking sounds from your car due to metals hitting one another.

9. Faulty Struts

Struts are used to stabilize vehicle movement and prevent your car from bouncing. Every v3hicle suspension system requires a strut to be able to maintain stability. The strut mount prevents vibration on your vehicle and unnecessary sounds. When your strut is faulty, your vehicle loses stability and balance. This can cause it to make unnecessary sounds and have increased vibration. If you observe that your strut is faulty, then you should take It for repairs.

10. Bad Control Arms

Vehicle control arms are used to balance the difference between the road and the tires. It is most useful when you are driving through potholes and uneven terrains. The control arms move alongside your wheels to compensate for the variation inroads. When your control arm is faulty, your tires begin to bounce off the road as you drive through potholes and rough roads. This can cause many noises and contribute to the knocking sounds you may be hearing under your car.

11. Bad Sway Bars

Sway bars are used to maintain vehicle balance when you go through a corner or turn. The sway bar helps to prevent your car from flipping over when you make a quick turn. Sway bars can break when they are under a lot of stress and when they do, it could be dangerous when making quick turns because your vehicle cannot maintain balance. This can also cause knocking sounds when you are making a turn through a corner. Make sure to change the sway bars when they get broken. Changing the sway bars is a technical job, and we recommend you consult a mechanic to do it for you

12. Steering Rack End Bushings

Your steering rack can cause a lot of noise when it is worn out. They move side by side to provide stability to the steering rack and the car frame. If your steering rack end bushing goes bad, you will experience unnecessary sounds from the steering.


A car will always give signs when it needs maintenance and repair. Most of these signs are through the sounds you hear. As a car owner, you should be vigilant about the type of sound that comes out of your car while driving. Please don’t ignore the sounds. It might be something big. Always ensure to check and identify any abnormal sounds and make sure your car is in perfect condition all the time.

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