Top 6 Reasons Why My Car Sounds Like a Lawn Mower (and How To Fix It)
Chris is Head of Content for FindTheBestCarPrice and is based out of Philadelphia, PA. As a seasoned automotive industry analyst and car enthusiast, he ensures the highest level of quality across all our content and curates our picks for the best deals each month.
Chris studied information systems and marketing at Drexel University and writes about a wide range of topics ranging from car buying tips to troubleshooting common mechanical issues.
When he’s not thinking about cars, he likes to stay in with his dog and make an “attempt” to finish a crossword puzzle (he’s not quite at the Saturday/Sunday level…yet). As a former cheesemonger, Chris still has a “sharp” passion for all things cheese, and his fridge is always loaded with it!
If you've noticed that your car sounds like a lawn mower, it can be a cause for concern. A car that sounds like a lawn mower can indicate various issues, from minor to serious.
The sound can be caused by several factors, ranging from a faulty muffler to a damaged exhaust system. Sadly, it can be hard to diagnose the problem yourself if you’re not an auto mechanic, but there are some steps you can take to troubleshoot the issue on your own.
Let’s explore the common causes of a car sounding like a lawn mower, including problems with the exhaust system, engine, and muffler. We will also give you some practical tips on the steps you can take to fix the issue.
Now, let’s learn more about how to deal with the issue of a car sounding like a lawn mower.
Table of Contents
Why My Car Sounds Like a Lawn Mower and How To Fix It
The following are the leading causes of your car sounding like a lawn mower:
1. Old Differential Fluid
Outdated differential fluid could be another culprit behind your car's lawnmower-like noise.
This fluid plays a crucial role in reducing gearbox friction. However, if it's old, cracked, or leaking, it can cause various issues.
Deteriorating differential oil can lead to problems such as overheating, gear lockup, and gear damage. The lack of proper lubrication can cause gears to generate excessive heat and potentially break.
Locked gears can bring your vehicle to a sudden stop, making it difficult to maneuver on rough terrain or corners.
How To Fix It
So, how can you fix this issue? If you suspect that the gears are causing the noise, it's best to seek professional help immediately.
Waiting too long to address the issue can further damage your vehicle. To prevent such problems, changing the differential oil every 30,000 to 50,000 miles is advisable to ensure optimal performance and minimize the risk of a lawnmower-like noise from your car's gears.
2. Engine Misfire
An engine misfire transpires when one or more cylinders fail to engender propulsive force. It can be instigated by various causative elements, including an obstructed spark plug, malfunctioning oxygen sensor, or obstructed fuel injector.
In addition, unburned fuel can ignite in the following cylinder, resulting in a sound similar to that of a lawnmower.
Driving with a misfiring cylinder can be hazardous. It may cause your vehicle to stall while driving, posing risks to yourself and others and potentially leading to accidents.
How To Fix It
Accurately diagnosing the issue is essential if your car sounds like a lawnmower due to an engine misfire.
You can discern a misfire by acutely discerning the acoustic emissions of your vehicle. If it exhibits irregular or uneven operation, it may be a symptomatic indication of an engine misfire.
As misfires can have multiple causes, it's best to consult a qualified technician to diagnose the problem accurately rather than guessing which parts need to be replaced.
Professional expertise can help you address the root cause of the misfire and resolve the issue effectively.
3. Bad Wheel Bearing
Wheel bearings are typically affixed atop a metallic tube to mitigate friction during vehicular motion.
However, these bearings are susceptible to rust and corrosion if not adequately lubricated regularly, potentially leading to a lawnmower-like noise emanating from your vehicle.
Symptoms of a malfunctioning wheel bearing include a pronounced noise as the wheel rotates, excessive play when the wheel is rocked, uneven tire wear, a wobbly steering wheel, and vehicle drift or pull while driving.
A failing wheel bearing can result in lateral movement, causing tire noise and impeding axle mobility. It can also pose significant risks, such as wheel lockup while driving.
How To Fix It
If you suspect a faulty wheel bearing due to the presence of lawnmower-like noises while driving, it is imperative to inspect each wheel individually for potential issues.
Safely raise the vehicle one tire at a time and slowly rotate the wheel to detect any metallic, crackling, or squeaking sounds.
Alternatively, you can roll each wheel separately to assess for failing wheel bearings. If the wheels exhibit such noises, it indicates a broken wheel bearing that requires immediate replacement to restore proper function and ensure safe driving.
4. A Blown Head Gasket
The head gasket is a critical component within your engine, tasked with sealing off the cylinders and preventing any leakage of coolant or engine oil to the outside.
Considering the extreme operating conditions of an automobile engine, characterized by high temperatures, overheating can pose a significant risk of head gasket failure.
A blown head gasket can manifest as a lawnmower-like noise and may even threaten your hearing, as it can release hazardous gases into your vehicle's interior.
Furthermore, a ruptured head gasket can adversely impact your vehicle's performance, resulting in reduced speed, potential engine failure, and costly repairs.
How To Fix It
Should you encounter a blown head gasket, it is imperative to seek the expertise of a skilled mechanic promptly.
They will ensure that new gaskets are utilized in the repair process, meeting or surpassing the original manufacturer's specifications.
To prevent head gasket failure in your vehicle, it is advisable to diligently maintain the engine coolant at the appropriate level and ensure it is mixed according to the manufacturer's recommendations.
This proactive approach can help mitigate the risk of head gasket issues and safeguard the performance and longevity of your engine.
5. Exhaust Leak
This phenomenon occurs due to the transportation of highly heated chemicals through the exhaust system, subjecting its components to considerable strain as they undergo expansion and contraction.
An exhaust leak can manifest as a noise reminiscent of a lawnmower when the vehicle is started or accelerated, making it relatively easy to detect through visual inspection of the exhaust system.
However, the consequences of an exhaust leak extend beyond just the noise, as it can release harmful gases into the atmosphere, compromising the cabin air quality and potentially causing failed emissions tests.
A matter of utmost concern lies in the indisputable fact that many harmful gases, including the insidious odorless carbon monoxide, can secretly permeate the passenger compartment, evading detection and thereby engendering grave health hazards such as asphyxiation and even mortal consequences.
How To Fix It?
To address this issue, a preliminary step involves running your vehicle and carefully placing your palm near the exhaust pipe without making contact to determine if the telltale noise indicates an exhaust leak.
Subsequently, it is imperative to seek the assistance of qualified professionals, as many exhaust system issues are caused by metal corrosion, necessitating specialized welding repairs.
In some instances, the replacement of bolt-on components or exhaust system repairs may suffice, but this is relatively rare.
Prompt action is crucial to mitigate the risks associated with an exhaust leak and ensure the safe operation of your vehicle.
6. Old Tires
Fresh tires bestow a smooth and noiseless ride upon your vehicle, owing to their resilient capacity to withstand friction. Conversely, tires that have worn out over time can emit a cacophony akin to a lawn mower.
Likewise, underinflated tires can also produce a similar din. Should your automobile start resembling a lawnmower in its auditory output, it is imperative to pull over and thoroughly examine the condition of your tires.
Driving on worn-out or underinflated tires poses various risks, including diminished road grip, tire blowouts, squeaking brake pedals, and even potential accidents.
Notably, poorly worn-out tires significantly elevate the hazards associated with driving. Even in dry weather conditions, they fail to establish a firm grip on the road, impeding proper steering and potentially causing the vehicle to skid when coming to an abrupt halt.
As such, it is imperative to diligently verify that your tires are inflated to the correct pressure levels and are appropriately aged.
How To Fix It
To rectify this issue, it is recommended to regularly check your tire pressure at least once a month, particularly before embarking on long trips or carrying heavy loads.
The prescribed tire pressure specifications from the vehicle manufacturer can typically be found on a sticker affixed to the driver's door or in the door jam and may also be referenced in your car's owner's manual for guidance.
