Causes of Car Makes Noise When Accelerating at Low Speed

New cars that just exited the dealership don't make any noise (well, most of the time). This is because each part is carefully dimensioned with tight tolerances, so everything works smoothly together. However, as the vehicle ages, it starts to produce more noises, some of which can indicate a serious issue with its various parts.

For instance, people report a common noise when accelerating at a low speed. The problem is that this noise is often not the same – some report clicking noises, and others report squealing sounds.

So, what is that all about? Well, there is a reason why we hear most car noises when accelerating and not when we travel in a straight line. And it's not just the noises themselves – it is the fact that cars are quieter when traveling at lower speeds.

But there is no simple answer to the "car makes noise when accelerating at low speed" issue since each sound has its own significance. So, let's have a closer look at the matter and see how we can quiet down your car and decode all noises!

Understanding Car Noises

Cars are some of the most complex machines on earth, with many mechanical complexities and thousands of parts that need to work in unison together.

From the engine's piston-driven orchestra to the harmonics of the suspension system, everything requires precision and tight tolerances to operate smoothly. In perfect conditions, these components produce a hum of operation, a sound often associated with a well-running vehicle.

So, of course, if there is an abnormality in the way these parts function, distinct noises manifest as the tell-tale signs of potential issues. But let's delve into more detail and see how you can maintain the mechanical concerto in your vehicle.

1. The Science Behind Vehicle Sounds

According to physics, sound is nothing more than a pressure wave created by vibrating objects. For instance, for a speaker to produce sound, it needs to vibrate the membrane in a certain way. The sound pressure then travels through the air (or any other medium) and is picked up by our ears as a unique auditory sensation.

When an automotive component starts to fail, it can vibrate irregularly, producing sound waves that deviate from the norm. In a well-maintained vehicle, these vibrations will be dampened and hardly audible, but deviations can result in everything from low-pitched, rumbling drones to high-pitched squeals, each indicative of specific mechanical issues.

A good example is a loose drive belt, which might produce a high-pitched squealing noise, as the decreased tension allows it to slip on the pulleys, causing friction and heat. Meanwhile, a damaged exhaust system might result in a low-frequency rumble due to leaks allowing exhaust gases to escape at points they're not meant to.

2. Recognizing Different Car Noises

Becoming familiar with car noises requires a lot of automotive knowledge and experience. Even some younger mechanics won't be able to find the problem after hearing the noise. At the shop I worked at, we had an experienced technician just for this – he was working over 30 years as a mechanic and knew where every sound came from.

But although it is hard to find every issue just by hearing it, you can learn about the most common noises on cars and diagnose them early. So, here are a few commonly encountered sounds:

• Clicking or ticking: these types of sounds will often be heard from the engine bay during acceleration and might suggest a lack of lubrication in the drivetrain. However, they could also come from the timing belt.
• Squealing or screeching: you will often hear these noises coming from the brakes due to worn pads. If similar noises come from the engine, it could indicate a slipping or wet serpentine belt.
• Rumbling or roaring: these noises are mostly associated with the exhaust system and issues like a bad muffler or any leak in the system. These noises can be very loud and hard to miss.
• Knocking or pinging: these noises indicate that there might be problems with the combustion process due to incorrect ignition timing or due to low-quality and low-octane fuel. These are serious problems that you should take care of immediately because they might lead to more serious issues down the line, like a damaged engine head, engine block, or pistons.
• Hissing: this sound often suggests a potential vacuum leak, an issue with the cooling system, or an exhaust leak close to the engine.

Please only use this list as a general guideline because, as I said, diagnosing any issue requires thorough inspection by an experienced mechanic.

Common Causes of Car Noises at Low Speed

Cars are louder when driving at higher speeds due to the more noticeable wind and road noise. Thus, it is much harder to notice any problematic sound because the white noise will use as a cover for it.

If you want to hear those problematic noises, you will need to drive more slowly and maybe open the windows. Whether it's the harsh scrape of a dragging brake pad or the irregular rhythm of a misfiring engine, you can hear the associated noises more easily at lower speeds.

In many cases, these noises originate from the engine, transmission, or braking systems, as these components are consistently engaged when your vehicle is in motion.

1. Engine-Related Noises

The engine is the most complex mechanism in your car, with many moving parts that need to work in unison together for it to work correctly. Any worn-out part, or problems with the fuel delivery and ignition timing, will produce vibrations, resulting in specific noises coming from the engine bay.

For instance, if you hear knocking or pinging noises during acceleration, it could indicate improper combustion. The issue happens because the air/fuel mixture is ignited other too soon or too late due to bad spark plugs, poor fuel quality, incorrect timing due to problems with the ECU, and even a buildup of carbon.

Meanwhile, a squeaking noise usually comes from the serpentine belt. In most cases, it is not the belt that is at fault but the pretensioners that keep it correctly tightened. If the belt is not properly tightened, it will slip against the pulleys, creating a high-pitched squealing noise. Wet conditions can also lead to the belt slipping a bit, also producing noises. However, this noise usually goes away after a short while.

Finally, a rhythmic clicking noise usually comes from an issue with the valve train. In most cases, it is because the components are not properly lubricated, but the valves might also need to be adjusted.

2. Transmission-Related Noises

Transmission noises are often most noticeable during gear changes and can manifest in various ways. Most often, the transmission will produce a humming noise due to insufficient lubrication. However, the same noise can originate from worn bearings. Whichever the reason, it would be a good practice to check the transmission fluid level or whether the oil pump works.

However, a grinding/crunching noise is a more serious issue that mostly plagues manual gearboxes. It is the result of a worn clutch or synchronizer, which, if not taken care of immediately, could wreak havoc in the transmission. That said, the same noises can be heard on automatic transmissions and indicate issues with the planetary gear set.

3. Brake-Related Noises

Brake noises are the easiest to identify, even by novice drivers, because they only originate when you apply the brakes. Most often, it is squealing noise that comes from the brakes, which results from worn brake pads.

Most pads have built-in wear indicators that scrape against the rotor when the material wears down, causing this noise as a warning to the driver. Thus, whenever you hear such noises, it is recommended to check whether the brake pads need to be replaced.

Some brake pads can produce a slight squealing noise, even when they have enough "meat" on them. This happens due to dirt or being trapped between the pad and the disc. However, it can also happen to modern brake pads that don't use asbestos as friction material due to environmental issues.

In these modern pads, the molecular vibration within the friction material creates a very annoying noise that indicates an issue with the system. However, the brakes are working just fine – it is only that they produce more noise than before. You can easily hear squealing noises coming from modern cars, and that is the reason why.

With that said, grinding, which is typically louder and more abrasive than squealing, could indicate that the brake pads are completely worn out, causing metal-on-metal contact between the brake caliper and the disc. You can't mistake this noise for the sound of a modern brake pad, and you should immediately replace the old pads.

These are just a few potential causes of low-speed car noises. It's important to note that while some of these noises might seem minor, they can often signify significant underlying issues that could lead to more severe and costly damage if left unchecked.

The Role of Car Speed in Noise Production

Car noises can occur at any speed, but the audible perception of these noises and their sources may differ significantly based on your vehicle's velocity. In other words, due to higher road and wind noise, you can't hear the noises that come from the car.

However, when you slow down, the ambient noise level decreases, and you're more likely to pick up on other sounds that were drowned out at higher speeds.

1. Why Low Speeds May Accentuate Noises

Accelerating from a stop is pretty hard on your car's components. It not only requires instant power from the engine, but it also puts significant strain on the suspension components. Not to mention, your transmission will need to shift through the gears to get you going, as opposed to being in one gear for most of the time when you are driving at a constant speed.

2. The Impact of Car Load on Noise Amplification

Another factor to consider, particularly when accelerating from a low speed, is the effect of the vehicle's load on noise production. When you're starting from a standstill or accelerating, more load is placed on the engine and transmission to get the vehicle moving, but it also affects the suspension components.

For example, accelerating puts more load on the engine mounts, which can produce more noise if they are worn out. Similarly, a worn suspension component might creak or groan when it's loaded and unloaded during low-speed maneuvers like turning or going over bumps.

How to Diagnose Noises When Accelerating at Low Speed

Unwanted noises in your car can be annoying, giving you quite the headache on longer journeys. Crucially, though, they are also concerning, potentially indicating a variety of mechanical issues.

If you hear any noises coming from your vehicle during acceleration, it is highly recommended to address the issue before it leads to more significant damage. In some cases, car makes noise when accelerating at low speed are also a safety concern, so taking care of them on time is crucial.

1. Steps for Diagnosing Your Vehicle's Noise

Although I would highly recommend bringing your vehicle to a good car service shop to diagnose any issue, you can follow some of my pieces of advice to find some problems yourself.

You should start by identifying the type of noise and its location. Pinpointing the noise might look easy, but trust me – it is sometimes very hard. You could spend hours trying to find where the noise comes from, especially if it comes from an unlikely area.

Still, as a rule of thumb, knocking or pinging sounds indicate engine-related issues, such as combustion problems. Furthermore, a whining noise might suggest problems with the transmission, such as worn gears or low transmission fluid. Moreover, grinding or squeaking noises could signal brake-related issues, like worn brake pads or a failing wheel bearing.

To further pinpoint the noise, though, you will need to replicate it. In this case, I would recommend repeating the conditions under which you heard the noise first. Does it only happen when accelerating or at certain speeds? Is it affected by the vehicle's load, or does it change when turning or braking? Noticing these patterns can help identify the source.

Sometimes, these weird noises, when accelerating at low speed, are the result of low fluid levels. Thus, it would be a great idea to check the fluid levels in your car. These include your engine oil, transmission fluid, power steering fluid, and brake fluid at appropriate levels.

Still, most of the time, you might need to visually inspect your car and, if possible, touch the affected parts to see whether they are loose or if there is a leak or damage. Use caution when inspecting under the vehicle or near moving parts.

2. When to Seek Professional Help

While some noises might be easy to diagnose and fix, others may require a professional's insight and expertise. If you're unable to identify the noise source, if the noise continues after your attempts to rectify it, or if you notice any changes in your vehicle's performance, I highly recommend seeking professional help.

This is particularly crucial if the noise is accompanied by the check engine light on your dashboard or any other light. That is because to find the culprit in these situations, you will need an OBD2 tool or potentially a laptop with the manufacturer's software installed. Auto mechanics have these specialized tools and the experience to accurately diagnose and address such issues, ensuring your vehicle remains safe and reliable.

Solutions to Noises When Accelerating at Low Speed

Naturally, to solve the noise when accelerating at low speed, you will need to address the underlying issue. For instance, you can solve some engine noises by putting in higher-quality fuel or solving pre-ignition issues, or transmission noises by changing the transmission fluid. Moreover, you can solve most brake noises by replacing the brake pads.

1. Maintenance Tips for Preventing Car Noises

Prevention is often better than cure, and that is particularly true when it comes to cars. Most issues that plague modern cars are due to late or insufficient maintenance.

So, don't be that guy/girl that skimps on fluid changes, which are crucial for the proper functioning of your car. I highly recommend following the manufacturer's recommended service schedule and changing the engine oil, brake fluid, transmission fluid, and coolant on time.

Furthermore, you should take care of your tires – they also require frequent maintenance. And the best way to do that is to make sure that they are properly inflated. Incorrect tire pressure can cause road noise and affect overall vehicle performance.

But it is not just maintenance that is important – timely repairs and part changes are also crucial in ensuring that your vehicle doesn't produce noises and stays drivable for longer. Regular visual inspections can help identify worn or damaged parts before they start causing problems. This includes brake pads, belts, and other components.

Finally, by maintaining your vehicle at a highly-rated service shop with experienced mechanics, you will allow professional technicians to spot problems even before they appear. These mechanics can see whether some parts are loose and need replacement, even before they affect other components.

2. The Cost of Ignoring Unusual Car Noises

You should never ignore a noise when accelerating at low speed because it could worsen over time. That only seems logical – a worn-down part, for example, will only become more knackered. I am still to hear about a car part that fixed itself.

Even worse, worn-down components and the vibrations they produce affect other parts, and not in a good way. Eventually, they will wear other components in your vehicle's engine, transmission, or braking system, resulting in hefty repair bills.

To add insult to injury, unresolved mechanical issues could pose serious safety risks, impacting your vehicle's handling, braking, or overall performance.

Conclusion

Has this article helped you to find the culprit for the noise when accelerating at low speed? I hope it did, but if it didn't, there is a plethora of car service centers that can help you with the problem.

Just make sure that you tackle it on time! I had a friend that didn't have any issue hearing the squealing noise coming from the brakes. Each time I asked him why he didn't replace the pads, he just said, "Oh, they will be fine." In the end, he also needed to replace the discs, which were far more expensive. Not to mention, the procedure is also costlier because more labor hours are involved.

Crucially, take your vehicle seriously because, in the grand scheme of things, it is a dangerous thing to be in. Car accidents still take many lives and leave many people injured, and they mostly happen due to driver negligence and poorly maintained vehicle. For instance, the story of my friend I told you could also lead to the discs breaking apart, leaving you with no braking force whatsoever.

So, take care of your car because it might just save your life!