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Why Is Your Car Making Humming Noise At 40 MPH?

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Imagine driving on a highway with no vehicles around you and you want to drive your car at a higher pace just to make your ride more pleasant but as soon as you speed up your car you started hearing strange noises, and you have had to immediately slow down your car since you are worried for your car. Wondering why is your car making humming noises at 40 mph speed or more?

What Happens When You Speed Up Your Car?

Driving at accelerated speed may be a thrill and can be really fun when you overtake cars around you. Weaving through the lanes and cutting around the curves can be exciting. But a lot of damage can happen to your car whenever you are speeding up your car,

Going faster intends your engine to use more gas or diesel per mile you drive and your transmission will also get wrecked, so whenever you accelerate your car more than usual it means you are putting extra stress on all the mall moving parts of your engine that will cause more wear and tear of your vehicles.

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Should You Drive Slow?

No Driving slow can at some points be even more dangerous than driving faster in some cases. In the Language of Law,

No person shall drive upon a highway at such a slow speed as to impede or block the normal and reasonable movement of traffic unless the reduced speed is necessary for safe operation, because of a grade, or in compliance with the law.

A lot of Accidents are caused when drivers drive too slowly in a speedy zone or by drivers who are driving in an unforeseeable manner. This is the kind of driving that causes accidents, not fast driving. So driving slow can save your car from inner damage but can invite a lot of accidents.

What Should Be The Average Speed To Drive?

The average speed of cars in the US is found out to be 66 mph posted with 55MpH. It means that speed from 55 to 66 Mph is normal speed, so if your car is making weird noises at 40 Mph there is for sure something wrong with your car. So to understand how to fix this it is necessary to understand the factors that might be causing those noises.

Why Is My Car Making Humming Noises At 40 Mph?

So the problem is when the car starts to make a humming noise, just like the bass on a stereo or as an airplane taking off as soon as you accelerate your car above 40 mph, and the sound keeps on getting louder and louder but after a certain speed the volume is consistent and after that whenever you take a turn, that noise gets even louder but if you turn the other way the noise disappears.

People often by mistake consider that noise like an engine noise but you should check your RPM Gauge to tell whether it’s coming from your engine or not. As you accelerate, the RPM and the speed gauges rise. Progress at a set speed and let off your gas pedal and see the RPM gauge drop, If there’s still that humming noise then it is not coming from your engine but your wheel bearing, if there isn’t that means the noise is coming from the engine.

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How To Reduce Humming Noise In Car When Accelerating?

There are two cases for these humming noises, one that it is coming from your engine and the second that your wheel bearing is making those noises. Let’s analyze both the cases below:

1. If Your Engine Is Making The Noise

If your engine is making the noise then there could be problems with cylinder compression. Due to the uneven air-fuel ratio in the cylinder, combustion can happen at rates higher or lower than normal. Whenever the pressure created in the engine’s cylinder is higher than usual then your engine starts to make noise.

The engine cylinder must be replaced if you try to ignore this problem then it could lead to the damaged engine, which will cost you a lot when you go for replacing the engine.

2. If It Is Your Wheel Bearing Making That Noise

Noise is the most common symptom of a bad wheel bearing, But there are dormant indications as well, such as making vibrations while driving. Whenever you are driving at low speeds, you will be able to feel only the vibrations, while at higher speeds they’ll make humming sounds.

If your wheel bearing is damaged and you keep on driving the vehicle without repairing those your wheels will start to wear out at a faster rate or your tire can be uneven and at extremities, your wheel can completely fall apart while driving, which can lead to hazardous results.

So it is very difficult to drive with wear-out wheel bearings and very dangerous too plus they can put extra stress on your hub, CV joint, and the transmission too.

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What Is The Average Cost For Repair?

The average cost of repairing does depend on the model of your car and the damage that happened to your machine but on average to replace your cylinder in the engine you will have to pay around $320 to $500. But if it is your wheel bearing then to repair it you will have to pay around $130 to $220.


The average speed to drive your car is nearly 55 mph and you should always drive your car below the legal speed limit that will help your car to reduce the damage that occurs whenever you drive your car at a higher speed that puts heavy stress on your car’s engine and also helps to reduce the risk of accidents.

But why is your car making humming noises at 40 mph speed or higher? Now you know that your car is definitely suffering from some problems that must be repaired since it is not recommended to drive your car while it is going through the damage, the damage can be there in your engine or your wheel bearing, you should always get your engine or he’ll bearing repaired if you hear such a sound as soon as you accelerate your car above 40 mph.

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