Don’t ignore the steady humming sound in your car! When it only happens when you accelerate, it’s a sign that a major rotating part is failing. Ignoring it means risking a breakdown or much more expensive damage later. Let’s look at the few simple places that humming noise when accelerating could be coming from.
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Reasons for Cars Making Humming Noise When Accelerating
In most cases, the humming noise during acceleration does not start until the car reaches 2000 rpm. It’s not a loud sound, although it’s not faint enough to be ignored too. The possible reasons for this sound could be:
Catalytic converter
To find out whether a bad catalytic converter is behind this humming noise, you’ll need to check it physically.
Tell someone to rev the engine while you go under the car. Check the muffler system underneath the engine area and then move on to the catalytic converter.
The converter looks like a basket woven with a bunch of wires. Rust in the converter could also cause this humming noise.

Bad bearings
To test whether it’s a bad bearing in any of the systems, you will need to warm up the tires. Choose a place with no traffic and then move the car back and forth frequently.
If it’s happening due to a bad bearing, the pitch will change. The culprit in this case is most likely to be a bad wheel bearing. Otherwise, the problem is with the tires.
Engine problems
Various engine issues can also cause a humming noise when accelerating the car. It’s hard to pinpoint the exact source of trouble because there are a couple of issues.
Sometimes it may even require a complete engine checkup to find out the troubling parts or area. In that case, you have to take the help of a professional mechanic.
If you want to do a checkup at home, look for leakage or a fault in the power system. A leak in the power steering or exhaust system can cause this annoying humming noise.
If there is a leak, you can do a quick repair, but a permanent solution will need a professional fix.
A low level of fluid or a defective part in the power steering system can also be another reason for the sound.
Just add more fluid if the level is low, and your car will be fine. However, fixing a faulty system will require a high level of automotive skill.

Steering issues
There are a couple of steering system problems that could be responsible for the humming noise. It could be a misaligned steering wheel or a loose steering belt.
When the steering wheel is not in the correct position, increasing the car speed will create a humming or whining noise.
The same problem will occur when the steering belt becomes loose. Both issues are quite dangerous as they can lead to accidents on the road.
Final Thoughts
In the end, that humming noise is your car giving you a clear warning. Since the sound only shows up when you step on the gas, you know the problem is with the parts that are working hard to move the car, like your wheel bearings or something in the driveline. Don’t put off this repair, as a small humming noise can quickly turn into a major, expensive breakdown. Getting the noise checked out as soon as possible is the best way to keep your car safe and your repair bill small.