Your Hybrid Cars Noise Is So Weird – Here Are The Reasons?

Hybrid cars (powered by electricity and gasoline) that operate too smoothly are being called “dangerous” by many people. There is an opinion that those hybrids need to be “noisier” a bit more. To solve this problem, many countries have requirements about hybrid cars noise. Specifically, plug-in hybrid and hybrid vehicles both have to make noise when driving at low speed (<30 km/h) to ensure safety for pedestrians.

Equipped with a sound-emitting system, we sometimes still hear the strange noise from Hybrid cars and we wonder whether it is just a normal hybrid sound or has some problem happened to your car? To understand more about the problem, let’s read the article below.

hybrid sound
Sometimes you will hear strange hybrid sounds and wonder what happened to your car? (Photo:

The reason why hybrid cars noise is so weird.

The hybrid brake is damaged.

Just like any other conventional car, the principle of operation of the brake is when drivers want to stop or slow down, the driver needs to apply enough braking force to make the wheels turn slowly or stop completely. But in the process, the car brake showed signs of failure. One of the most obvious signs is the noise when braking. What causes this phenomenon? The reasons can be:

  • Worn brake pads: If the brake pads are used for a long period of time, the rear metal surface will slowly wear down. This causes the metals to collide with each other and will create noise.
  • Pads are torn: A torn pad will create conditions for parts of the brake system to expose to each other like rotors. 
  • Bad brake rotors: Worn brake discs are the reason for the annoying noise from the brake system. Brake discs that are no longer flat will cause a weird sound.

Fail automated gearbox

EVs and HEVs often use direct or automatic transmissions. When the Hybrid gearbox is damaged, you can hear some obvious sounds like chattering noise, vibration, and metal banging sound. 

Some causes that can be mentioned are the improper use of automatic transmission such as carrying heavy loads, often running on uneven roads, shifting gears when the car is driving at high speed, or before completely stopping… All of these errors cause the engine to overheat, making it difficult to shift gears.

Besides, the other reasons can be listed: worn gearbox, wheel bearing damage, or driving a car in harsh conditions continuously. If the pump shaft or machine is faulty, you may hear a humming sound.

A hybrid engine has a problem

As you know, unlike diesel and petrol engines, Hybrid motors produce much less noise. HEV engine is made of power and gasoline from the battery. Although it is much quieter, drivers sometimes will hear the odd noises: grinding, tapping, clicking, knocking…from the car engine and it may raise your concern. The causes of this include a dirty air filter, a damaged spark plug or spark plug wire, a clogged fuel filter, or a catalytic converter.

hybrid engine
Check the hybrid engine to fix it immediately (Photo:

Type of hybrid car sounds

All noise emitted from a Hybrid car means that your car has a problem? The answer is “No”.There are many types of hybrid cars noise, it can easily make you confused about the condition of your car ” Whether one of the parts in the car is damaged?” Below we will cover some types of good noises, you don’t need to worry when hearing it:

  • When the Hybrid engine stops, the cooling system pumps some hot coolant into the thermos tank, you can actually hear the pump humming for a few seconds as it fills the thermos tank.
  • If you’re driving at low speed, you hear a strange noise and ask yourself: What happened to my Hybrid car? In this situation, your car is totally normal. Specifically, the Acoustic Vehicle Warning System (AVAS) of EV and HEVs must make a clear and continuous sound when the car is moving at a speed of less than 19 km/h so that pedestrians know that the car is moving. The volume of this system is allowed to range from 56-75 decibels (similar to a conversation indoors, or an electric toothbrush). The noise of the sound emitted will rise when the car is accelerating.
  • The only noise EVs tend to make is the noise made by the tires or created by wind resistance, and that only happens at higher speeds.

>> See more: 6 Questions to Ask about Hybrid Car Maintenance


Why is Toyota Prius making loud engine noise?

Toyota Prius is the world’s first mass-produced hybrid (gasoline-electric) vehicle. At the same time, it is also a popular car model because of its fuel-saving advantages and environmental friendliness. But there are some complaints about the noise of this car. Problems can range from as simple as a dirty spark plug to a more serious damaged silencer or catalytic converter.

Do hybrid cars need to be charged?

With a full-hybrid or mild hybrid, the car does not need to be charged because the internal combustion engine will both take over the driving role and provide power for the hybrid battery. As for plug-in hybrid cars, the battery needs to be charged by an external power source.

How to maintain a Hybrid battery?

Basically, the battery does not need periodic maintenance, the part that needs to be maintained periodically is the air filter in the cooling system. This air filter needs to be cleaned every 10,000 km and replaced every 30,000 km.

>> Related post: Can You Drive A Hybrid Without The Battery?