In 1990, Toyota launched Lexus with a stunt that still feels like a flex. An LS 400 sat on a treadmill, hitting speeds over 140 mph. On its hood rested a pyramid of 15 champagne flutes. The engine revved. The glasses didn’t wobble. It was proof of precision. It was also proof that luxury meant silence.
That commercial worked. Buyers who once dreamed of BMW or Mercedes saw a Japanese car that didn’t rattle their teeth. But did the stunt actually prove engineering superiority? Or did it just prove that people care deeply about how a car feels?
It showed that premium buyers measure quality by vibration. Specifically, the less engine vibration reaches the cabin, the better. Any driver who has sat in a cheap econobox knows the difference. Shaking hands. Fatigue. Discomfort.
This falls under NVH —Noise, Vibration, and Harshness. It’s the metric that decides if you buy a car or just walk away. And engine vibration deserves the most scrutiny. It impacts comfort. It drains endurance. It kills durability by causing premature wear.
Let’s look at how engineers fight it. Starting with five innovations.
Flexible Engine Mount Pieces
Engine mounts are the first line of defense. They stop shakes from propagating through the entire vehicle.
But first, why do engines vibrate at all? Internal combustion is a series of controlled explosions. They are forceful. Inside the block, pumping and rotating parts have mass. When they move, they react against the engine block with equal and opposite force. Multiply those reactions by thousands per minute, and you get vibration.
It’s natural. We just don’t want to feel it.
Mounts are metal flanges attached to the engine and the bay walls. They contain thick grommets or blocks of polyurethane or rubber. These absorb vibration energy. If you feel new shakes in your cabin, check the mounts. Worn mounts are obvious—cracked rubber. Torn material. Sometimes the rubber collapses internally without visual signs. A qualified technician can spot this.
Also check the transmission mounts. They do the same job for the gearbox. Heavy-duty shaking from the transmission needs insulation too.
Body Stiffening Techniques
Keeping vibration in check starts with a solid foundation. The frame. The skeleton.
A rigid frame resists flexing. It resists bending. It stops annoying vibrations from traveling. Adding crossbars—also called stabilizer bars—helps reduce body flexing. It makes the vehicle stiffer.
Squeaks and rattles often come from loosely assembled frames. Wide tolerances in construction make it worse. In the auto business, this is “fit and finish.” It asks: how much attention to quality and precision did the builders devote?
Poor fit and finish, combined with a flexing frame, amplifies engine vibration. The noise sounds worse. The feel is jarring.
To hunt down vibration, you sometimes have to go to the source. Our next fighter might spark recognition among experienced wrench turners.
The Anatomy of Engine Vibration
NVH splits into two varieties. Airborne and structural. You hear airborne disturbances. You feel structural ones.
Airborne disturbances are higher frequency sounds. They sit in the 300 Hz range and above. Engineers counteract them by eliminating them at the source or deadening them with sound-dampening material in door and body cavities.
Structural disturbances happen at low frequencies. You feel them more than you hear them. They travel through the seat, steering wheel, and floor pan. Engineers must measure and mitigate these unpleasant sensations. Vibration energy gets transmitted to your hands, feet, and even the seat of your pants.
Stiffness is usually an insult for people. For vehicles, it’s a compliment.
Misfires remain a primary suspect when an engine shudders. Modern ignition and fuel injection systems, featuring superior spark plugs and intelligent engine management computers, are significantly more reliable than the distributor-based setups of the past.
Still, misfires happen. During a misfire, one or more spark plugs fail to ignite the fuel mixture at the programmed moment. This failure in one or more combustion chambers disrupts the piston rhythm. The crankshaft feels the hiccup. Vibration follows. Jerking is common. Stalling is possible.
If you cannot distinguish between a sick engine’s spasmodic vibrations and merely old, sluggish performance, technology has your back. A misfiring cylinder or faulty spark plug will almost certainly trigger the check engine light on any modern vehicle. From there, you can use an affordable diagnostic reader to identify the issue. Alternatively, take the car to a local shop. A technician can pinpoint the problem.
Unwanted engine vibration is fundamentally a lack of harmony. Internal combustion is a violent process. Our next innovation attempts to impose order on that chaos.
The Role of Harmonic Balancers
Examine an automobile crankshaft up close. It is heavy. It is tough. It must be. It withstands thousands of explosive piston strokes per minute.
Despite its durability, the crankshaft twists and flexes under the pounding from pistons and connecting rods. It transmits unwanted vibration throughout the engine and the rest of the vehicle. At certain RPMs, the crankshaft can reach resonance. This is a state where it vibrates at a frequency capable of causing catastrophic failure. Think of the commercials where a singer shatters a wine glass with a high-pitched note. That is resonance.
In 1911, Frederick Lanchester invented a solution. He designed a device to bolt onto spinning crankshafts. The goal was to eliminate or reduce these problems. The harmonic balancer was born. It is also known as a vibration damper or crankshaft pulley.
The balancer dampens the shearing and twisting forces imparted by the pistons. To absorb the crankshaft’s tremendous energy, the balancer includes a section made of rubber or filled with energy-dissipating fluid.
We have looked at passive methods to prevent or muffle engine vibrations. The next innovation takes a different approach. It goes on the attack to keep bad vibes at bay.
Shaving Weight and Risking the Shakes
Harmonic balancers are heavy by necessity. They must counter the considerable rotating mass of the crankshaft. In high-performance car customization, however, weight kills horsepower.
Many speed enthusiasts replace factory harmonic balancers with lighter aftermarket versions. Some remove the units entirely. The goal is to go faster.
The trade-off is harsh. You get a shakier ride. You potentially cut short the life of your engine.
Active Vibration Control
Think about those pricey noise-canceling headphones you see in every gadget catalog. They don’t just block sound; they fight it. A tiny microphone picks up the background hum, creates an identical sound wave, but flips it 180 degrees out of phase. When that inverted wave hits your ear canal, it cancels out the original noise. The result is either crystal-clear audio or just pure, quiet silence.
Cars use this exact principle for active vibration control.
It’s not magic. It’s physics applied to the chassis. A company called Trelleborg Automotive built a system where a microphone listens for specific vibration frequencies inside the cabin. When it detects a rumble, the car’s computer generates an equal but opposite counter-vibration. An electromagnetic actuator, technically known as a “shaker,” fires off these counter-waves at strategic mounting points. Usually, that means the steering wheel or the footwell.
“An electromagnetic actuator, called a ‘shaker,’ transmits the counter vibrations at select mounting points, for example, the steering wheel or the foot well of the floor pan.”
The goal is simple: reduce the clatter, rattle, and rumble that seeps into the cockpit from the engine.
Is Active Vibration Control Safe?
There’s one downside to consider. If the system works too well, it might mask symptoms of a real mechanical failure. You won’t feel the subtle shudder that usually warns you about a failing mount or a misfiring cylinder.
But here’s the thing. The car isn’t blind. You’ll still get a check engine light or another dashboard warning if things go south. The vibration control doesn’t hide the engine’s internal struggles; it just smooths out the ride for you.
Engine vibrations happen for a lot of reasons. Lucky for us, these innovations give us effective ways to battle unwanted noise and shake.
Engine Vibrations FAQ
How do I stop my engine from vibrating?
One method is active vibration control. The system responds with an equal but opposite counter-vibration. An electromagnetic actuator, called a “shaker,” transmits the counter vibrations at select mounting points, for example, the steering wheel or the foot well of the floor pan.
Is it normal for engine to vibrate?
Yes, it’s normal for the engine to vibrate while in use. But if the vibrating engine is exceeding normal levels or accompanied with a rattling noise, that could be a sign something is wrong with the engine.
What causes vibration in engine?
Five reasons your engine might be vibrating include worn out spark plugs, loose or disconnected hoses, broken motor mounts, faulty adjusted fuel intake system or faulty timing belt.
Can low engine oil cause vibration?
Yes. Not only can low engine oil cause vibration, but so can low quality engine oil.
How does engine vibration impact drivers?
Of all the reasons a vehicle can shake and rattle while it’s on a roll, engine vibration deserves special scrutiny because it can have an impact on driver and passenger comfort, driver endurance and vehicle durability — since vibration causes premature wear and tear
