If you’ve noticed your car getting loud, growly, or just off, you’re not alone—and it’s something you should never ignore.
In this article, I’ll break down the most common causes behind this sound, so you can understand what’s going on and what to do next.
1. Exhaust Leak – The Most Common Culprit
If your car starts sounding like a lawn mower, an exhaust leak is often to blame. The exhaust system helps quiet engine noise and manage emissions. If any part of it gets damaged—especially the muffler, exhaust pipe, or manifold—the sound gets louder.
How to tell:
- Loud roaring or choppy noise
- Gets worse when you accelerate
- You might smell exhaust fumes
2. Damaged or Rusted Muffler
Your muffler is supposed to make the engine quieter. But over time, it can rust, crack, or fall apart, especially if you drive in areas with moisture, salt, or rough roads.
When the muffler stops working, your engine’s sound will come through raw—like a lawn mower at full speed.
Fix:
You’ll likely need a muffler repair or replacement—a fairly common fix I handle often.
3. Engine Misfiring
A misfire means one or more cylinders aren’t firing the way they should. That makes the engine run rough and noisy—think uneven puttering or popping.
Watch for:
- Check engine light
- Shaking or jerking
- Low fuel efficiency
4. Broken Manifold or Gasket
Your engine’s exhaust flows through the manifold before entering the full exhaust system. If it cracks—or if the gasket between it and the engine fails—you’ll hear a ticking or choppy noise, especially when starting cold.
This can mimic a lawn mower sound and should be addressed before it worsens.
5. Loose Heat Shield or Parts
Your car has metal shields around the exhaust system to protect other parts from heat. If they get loose or rusty, they’ll rattle like crazy, especially when driving or idling.
The noise may sound like a mower—or a bunch of cans dragging behind you.
Fix:
I can tighten or replace these quickly at the shop.
6. Aftermarket Modifications
If you (or a previous owner) installed an aftermarket muffler, exhaust tip, or cold air intake, it may be designed to sound louder. Some of these mimic that deep, growling tone—on purpose.
So ask yourself: Is this noise new, or has it always sounded like that?
What You Should Do Next
As a mechanic, I recommend:
- Listen closely — Does the sound change when you speed up?
- Check your dash — Any warning lights on?
- Bring it in — A simple check can save you major repair bills later.
Conclusion
Lawn mower sounds from your car usually point to an exhaust problem, engine misfire, or damaged muffler. These issues can be noisy, annoying, and harmful to your car’s performance—and your wallet—if you wait too long.
I help customers fix this issue all the time, and most repairs are quick and affordable if caught early.