Why Does My Car Sound Like a Lawn Mower? Causes and Fixes

Why does your car sound like a lawn mower? It is a common concern for newbie drivers. This common sound is not just a noise but an indication of some fault under the hood. In some cases, it can point to serious mechanical or safety issues. But don’t worry. In this guide, I will highlight the common causes of cars sounding like lawn mowers, identification techniques, and possible fixes.

Table of contents

• Common Reasons Your Car Sounds Like a Lawn Mower
• How to Diagnose a Car That Sounds Like a Lawn Mower
• Risks of Ignoring Lawn Mower Sounds
• Fixing a Car That Sounds Like a Lawn Mower
• Conclusion
• FAQs

Common Reasons Your Car Sounds Like a Lawn Mower

Let’s discuss the common reasons your car sounds like a lawn mower when idling or accelerating. I will explain which component faults can cause this sound and what issues might exist in each specific component.

1. Exhaust System Problems Can Cause Lawn Mower Sound

The key function of an exhaust system is to channel harmful gases away from the engine and reduce noise. However, if there is a leak or damage, the car will sound like a lawnmower when idling or when accelerating. There might be several issues with the exhaust system, which are listed below:

Rust and Corrosion: Exposure to moisture and road salt can create holes or cracks in pipes and mufflers.

Damaged Muffler: A broken or rusted muffler fails to dampen engine noise, creating a lawnmower-like sound.

Loose or Broken Components: Exhaust hangers or brackets can fail, causing pipes to move or vibrate. This can produce lawn mower sounds in your car.

Faulty Catalytic Converter: Cracks or clogs in the catalytic converter can allow exhaust gases to escape prematurely, making the engine sound rough.

If you find any of these issues, never ignore them. They can reduce fuel efficiency, decrease engine performance, and cause other issues as well.

2. Lawn Mower Sound in Car Due to Engine Misfires and Spark Plug Issues

If your car sounds like a lawnmower, the issue might be engine misfires and damaged spark plugs. Signs of spark plug problems include:

• Rough idling or difficulty starting the engine
• Poor acceleration
• Decreased fuel efficiency

Whenever you detect the issue in the spark plug, adjust it quickly to restore engine performance and get rid of the lawn mower sound. If not fixed on time, you might face other issues like car hesitation or engine stalling.

3. Catalytic Converter Problems

Car drivers usually ignore or do not notice the issue in the catalytic converter. If there is something wrong with the catalytic converter, your car may sound like a lawnmower. Catalytic converters filter harmful exhaust gases and reduce engine noise. If it gets damaged, the following thing might happen:

• The engine emits loud, rough sounds similar to a lawnmower or chainsaw.
• Your car may fail emissions tests.
• Harmful gases may leak into the environment.

Therefore, if there is an issue in the catalytic converter, repair or replace it quickly.

4. Air Conditioning Noise Issues

If you feel that the sound like a lawnmower is coming from the AC, the issue might be with the compressor, fan, or belt. The key reason behind the strange lawnmower-like noises from the car’s AC is worn components. Moreover, if the AC components are old and there is mold inside them, you can also experience a vinegar smell from the car’s AC.

5. Timing Belt and MAF Sensor Concerns Can Cause Lawnmower Sound

A damaged timing belt and the MAF sensor can also produce a lawn mower sound in your car. A frayed or damaged timing belt can create unusual engine noises.

The MAF sensor monitors the air entering the engine. If MAF does not work properly, it can cause idling and car hesitation upon acceleration.

How to Diagnose a Car That Sounds Like a Lawn Mower

When your car sounds like a lawn mower, finding the right cause is key. Here are the ways to diagnose the issue:

• Listen Carefully: Determine if the noise occurs while idling, accelerating, or using the AC.
• Check Under the Hood: Inspect spark plugs, belts, and exhaust components. Look for rust, cracks, or loose parts.
• Test the Exhaust: Tap on the muffler and catalytic converter gently to detect leaks or rattling sounds.
• Seek Professional Help: Still, if you are not able to find the cause and fix it, seek help from a qualified mechanic.

Risks of Ignoring Lawn Mower Sounds

You can’t ignore the lawnmower sound in your car due to the following risks:

• Health Hazards: Leaking exhaust can release carbon monoxide into your car cabin.
• Decreased Performance: Engine misfires or exhaust leaks can lower fuel efficiency and reduce acceleration.
• Costly Repairs: If you ignore the noise at the start, the issue will get critical.

Fixing a Car That Sounds Like a Lawn Mower

Now, we have discussed the causes of your car sounding like a lawnmower and steps to diagnose the issue. Here I am sharing some easy techniques to get rid of sounds like a lawnmower:

• Exhaust Repairs: Patch small holes, replace rusted pipes, or install a new muffler.
• Replace Spark Plugs: Swap worn plugs and ensure proper gaps.
• Catalytic Converter Replacement: Install a new or repaired converter if it is faulty or stolen.
• Timing Belt or MAF Sensor Maintenance: Replace or repair components as needed.
• AC Service: Check the compressor, fan, and belts for damage.
• Regular vehicle maintenance: Regular maintenance keeps your car running well and safe from bad noises.

Conclusion

In short, if your car sounds like a lawnmower, it can be due to minor wear, serious mechanical problems, or safety problems. Timely inspection and repairing the issue keeps you safe from costly repairs and prevents health issues as well. Whether your car sounds like a lawnmower while idling or accelerating, pay attention to the problem and fix it quickly or get help from a professional.