Car Sounds Like A Lawnmower – Explained

Car Sounds Like A Lawnmower – Explained

Hearing a sound like a lawnmower coming from your car can be irritating and scary. It also indicates that your vehicle is not in good condition and needs urgent attention.

But what exactly makes your vehicle produce a sound like a lawnmower? Many factors cause this sound, and understanding them will help you diagnose them as soon as they occur.

Car sounds like a lawn mower

This article will explain what makes your car sound like a lawnmower, how to diagnose them, and even their dangers.

Causes Of A Lawn Mower Sound In Your Car

Now, let’s dive into what makes your car sound like a lawnmower. Of course, there are many factors, but we will discuss only the six major ones in this article. They include:

1. Blown Head Gasket

A head gasket is a component that separates the engine and the cylinders in your car. It performs two significant roles in a car.

Firstly, it seals the combustion gases in the gas cylinder, thus preventing them from entering into the cooling system. Secondly, it prevents coolant oil and water from entering the cylinder.

These two roles ensure sufficient cooling of the engine, thus maintaining the power supply and speed of the car.

A blown head gasket is a result of overheating. The overheating causes the engine and the head to expand at different rates, such that the gasket will no longer fit into the area between the cylinder and the engine.

Overheating happens when the engine is left running for long without regular fluids change. The blown head gasket will then produce a knocking sound that makes your car sound like a lawnmower.

The knocking sound is due to the difference in pressure between cylinders. The one with higher pressure knocks on the one with lower pressure.

Dangers Of A Blown Head Gasket

A blown head gasket is very harmful to your health. It is because the lawnmower sound produced can affect your earing. Also, a blown head gasket usually releases harmful gases that will eventually enter your car’s cabin.

A blown head gasket is also dangerous to your car. It lowers the car’s speed and even causes the engine to break down, costly for you.

Therefore, you should always check the cause of the lawnmower sound in your car to rule out a blown head gasket before it causes further problems to you and your car engine.

2. Exhaust Leak

An exhaust system is another vital component in your car located at the bottom of your vehicle and runs from the engine towards the vehicle’s back.

It performs two essential roles: transporting burnt gases out of the engine and catalyzing the gases into less harmful substances that can be released into the environment.

This system usually wears down over time, resulting in a leak. It occurs because it transports very hot substances that cause stress on its components due to expansion and contraction.

It also transports vapor which causes the components to rust. Finally, since it is located at the bottom of the car, it is exposed to dust, salt, water, and ice.

An exhaust leak will make your car sound like a lawnmower due to the leaking gases. It typically happens when you are starting the vehicle or during acceleration.

However, this sound may be interrupted by the car vibration and the screeching of brakes; hence the best way to identify it is by physically examining the exhaust system.

To check if an exhaust leak produces the lawnmower sound, start your car and move your hand along the exhaust pipe without touching it since it can burn your hand. If there is a leak, you will feel the gas tapping on your hand.

Dangers Of An Exhaust Leak

Suppose your car sounds like a lawnmower due to an exhaust leak, then it indicates that harmful gases such as Carbon monoxide are entering the cabin.

Carbon monoxide is very toxic since it causes suffocation and even death; hence you should repair the exhaust leak as soon as you identify that it causes the lawnmower sound.

3. Failed Wheel Bearing

Its wheels must be solid and steady for a car to work well. It is achieved by using wheel bearings. A wheel bearing is a collection of balls joined together in a race. These wheel bearings are then firmly fitted into a hollow metal.

The wheel bearings usually ride on a metal axle shaft, thus reducing friction during locomotion. Since there is no regular lubrication of these bearings, they ought to be very tight not to be exposed to rust-causing substances.

But like any other component, they are prone to wear and tear, and they lose their sturdy nature somewhere along the way.

When the wheel bearings fail, they make your car sound like a lawnmower. It is because they allow the wheels to move from side to side.

To test if the sound produced results from failed wheel bearings, try to roll each wheel independently. If the wheels make this sound, the wheel bearings have failed and need immediate mechanical attention.

Why does my car sound like a lawn mower

Dangers Of Failed Wheel Bearings

A failed wheel bearing can be disastrous to your wheels since they cause them to wear down due to the sideways movement. Also, a failed wheel bearing can lock the axle, thus totally inhibiting locomotion.

Therefore, it is essential to listen and heed the sound produced by your car.

4. Engine Misfire

Engine misfire is another thing that makes your car sound like a lawnmower. One of the cylinders fails to produce power due to a faulty spark plug or worn-out oxygen sensor.

As a result, there will be unburnt fuels ignited in the next cylinder by a spark. Again, this ignition produces a sound resembling a lawnmower.

To know whether their sound is because of engine misfire, listen to the sound produced by the engine. If the sound is different from the usual sound, there is an engine misfire.

Dangers Of An Engine Misfire

An engine misfire can make your car come to a halt during driving. It is not only dull but also dangerous since it can cause accidents.

It tells you that you should take it seriously whenever your car sounds like a lawnmower or when it starts misfiring.

5. Old Differential Fluid

Old differential fluid is another thing that makes your car sound like a lawnmower. Differential fluid is a fluid that reduces friction in the gearbox.

This fluid has to be changed after around 30,000 miles. But in essence, the time you should change the fluid depends on the car’s model.

To identify if the sound results from the differential fluid, check if your car uses front or rear differential fluid using your car’s user manual.

Then, if your vehicle uses the rear differential fluid, change the gears while listening to the sound produced by the rear gears.

Dangers Of Old Differential Fluid

Old differential fluid can be harmful to your car in several ways. First, it fails to reduce friction in the gears, thus generating heat that could destroy them.

Also, it makes the gears lock, thus making the vehicle come to a halt. Finally, it makes it hard for your car to make corners on an easy road.

Therefore, you should listen carefully to the sound made by your car to make sure that it is not coming from the gears, and if it is, then you should see a mechanic immediately.

6. Worn Out / Underinflated Tires

Tires that are still new offer a smooth and silent ride. It is because they can easily withstand friction. On the other hand, old tires with uneven wear and tear make your car sound like a lawnmower.

Also, tires that are underinflated tend to produce a similar sound. Therefore, stop it and inspect the tires if your car starts sounding like a lawnmower.

Dangers Of Worn-Out / Underinflated Tires

There are many dangers associated with driving using worn-out or underinflated tires. They include less grip on the road, reduced braking ability, blowout of tires, and even accidents.

Therefore, you should ensure that your tires are fully inflated. Also, your tires should not be old.


If you wondered what makes your cat sound like a lawnmower, we hope that you have found an answer.

The major causes include blown head gasket, exhaust leaks, failed wheel bearings: engine misfire, old differential fluid, and worn-out or underinflated tires.

It would be best if you thus examined them whenever you find yourself asking this question.

Kindly note that what makes your car sound like a lawnmower could also cause other disastrous effects to you and your vehicle. For instance, a blown head gasket can damage your engine.