If you notice any strange sounds coming from your car, you should take it to a mechanic. This rule applies to all noises: loud, quiet, squeaking, ticking… you name it.
Any noises developing under acceleration are related to increased engine load.
The problem might be a mundane, straightforward fix. However, it might be as serious as an overheating engine, potentially ending in a seizure. Not good.
In this simple guide, I will run through some of the most common causes of a loud engine when accelerating. No matter the root cause, it’s worth taking your car to a mechanic for:
- Inspection
- Diagnosis
- Repair
- A check-up
- A tune-up
- A service
Even if you succeed in stopping the noise, it is crucial to inspect for any lasting harm.
Without any further ado, let’s talk about these loud noises your car’s making under acceleration!
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Why Does My Engine Sound Louder When Accelerating?
It is entirely normal for engines to get louder when you accelerate.
In an automatic vehicle, the transmission shifts down a gear (or two or three). In a manual, you’ll do this yourself. By doing so, the engine is forced to rotate much quicker to maintain the same speed.
The swifter your engine turns (“revolves”), the more noise it’ll make. That’s why it’s so much louder in your car on the freeway than when driving around town.
Engine speed is measured in revolutions (“revs”) per minute, or RPM.
However, if your car engine is noisier than usual when accelerating, there could be a deeper issue.
What Loud Sound Is The Engine Making Under Acceleration?
This guide will be split into the different sounds you might be hearing. It will then suggest some common issues based on the noise.
Loud Engine Noise Under Acceleration – Normal, Just Noisier
If your engine sounds louder under acceleration, you could have a blowing exhaust.
When an exhaust blows, the gases escape somewhere before the tailpipe.
It’s possible to find where your exhaust is emitting, provided you do so carefully.
- Park your car on flat ground. Do this with a friend so someone can help you if you run into difficulties.
- Leave the engine switched on, put it in Park, and apply the parking brake.
- Get underneath the car.
- Follow the loud, deep sound to its approximate origin.
- With your hand, you’ll feel exhaust gases escaping. Bear in mind that these might be hot, so don’t scald yourself.
- Take note of the specific pipe with the blow. This is the only one that needs replacing.
Usually, exhausts blow somewhere in the piping (due to moisture buildup and rust), in the muffler (at the rear), or at a connecting sleeve.
That said, it’s always possible for a hole or crack to open up in the manifold or the downpipe. These two segments, the initial two channels the gases travel through after leaving the engine, are found at the front of your car.
If they’re blowing, your engine will sound noisier all the time. However, it’ll be especially pronounced under acceleration.
Squeaking Or Squealing When Accelerating
Are you noticing a squeaking or screeching sound from your engine when you speed up? If so, check the serpentine drive belt before anything else. It’s by far the most probable cause.
You will notice a shrill sound that follows your engine speed. When you accelerate, the noise will increase.
Open the hood. That big black belt you can see looping around several pulleys? That’s the one to look at.
When a belt starts to get brittle or loses tension (for some reason), it can’t “hold onto” the pulleys.
Think of it a bit like your tires. When they slip on the road, you hear that tire screech. It’s the same thing for the rubber belt outside your engine.
So, as you’re checking your belt out, does it look frayed or worn? Is it loose? It should be tightly attached to the pulleys with no signs of wear and tear. If you notice any warning signs, replace the belt.
While you’re there, run the engine. Of course, you should ensure it’s in Park with the parking brake on. Remove any loose items of clothing or anything that might snag.
Are all the wheels spinning? If the belt is passing across one that’s seized, it’ll create the same squeaking noise. In this case, you’ll need a new wheel too.
Take your car to a mechanic. They’ll use the tensioner – inbuilt or otherwise – to remove the old belt (and maybe a pulley) and replace it.
Banging Or Knocking
A banging or knocking noise under acceleration could be caused by defective motor mounts or bearings.
As you accelerate, the banging noise might come from the engine block leaning backward. You know how you get thrown back in your seat when you slam your foot down? That’s what’s happening to your motor, too.
The block will move around as the forces acting on it constantly change. This could create a banging-type sound.
Although new bearings and mounts aren’t too difficult to replace, mechanics will need an engine hoist. Depending on the damage, they might need to spend some time repairing the immediate area too.
As such, it’s difficult to put a figure on the repair cost. Expect to pay at least $75 per hour, plus parts. This will likely end up somewhere around $400 to $700.
Tapping, Ticking, Or Clicking
A ticking or tapping sound is often a sign of wearing down components. In some cases, it’s nothing to worry about. All cars and engines have limited lifespans. They aren’t immortal.
However, it could also be a sign of low oil. You’ll probably see the temperature gauge start overheating, too. This tapping/clacking could be components striking each other where they aren’t lubricated sufficiently.
Park on level ground and turn your engine off. Check your oil level using the dipstick. Is it low? Top it up, ensuring you use the correct motor oil (check your owner’s manual).
Other potential causes include issues with the valvetrain, spark plugs, and camshaft.
If it’s getting especially bad when speeding up, you might like to consider either:
- Fuel and oil additives – these clean a lot of the gunk out of your engine.
- A service – new oil, spark plugs, fluids, and potentially a battery will give your car a new lease of life.
- A major engine service – paying a professional to disassemble your engine will be costly. Think in the thousands. However, there’s no better way to do a deep clean and replace any worn metal or rubber components.
Sometimes, cars just make sounds. It might be nothing to worry about. That said, take your vehicle to a mechanic and let them tell you that. Don’t sit back, do nothing, and hope for the best!
Grinding Sounds
Grinding sounds under heavy acceleration isn’t good. It’s rarely a simple, damage-less fix. Prepare yourself for what could be a significant repair investment!
If you hear a grinding sound coming from your engine as you accelerate, immediately pull over. Should your transmission break while driving, you’ll be in a highly perilous situation. At the side of the road, call for breakdown assistance.
The grinding noise you’re hearing isn’t likely to be the engine, contrary to what you’ll read on the internet. Well – if it is, it’s probably beyond rescuing.
It’s more likely to be your transmission or a driven rotational component, such as a CV axle. It could be a catching brake pad or a badly breaking wheel bearing.
Whatever it is, it’ll need removing and either replacing or rebuilding. A transmission rebuild could cost you a few thousand dollars. For the other jobs, expect to pay between $200 and $500.
What’s The Most Likely Reason For A Loud Noise When Accelerating?
If your engine simply sounds noisier, check for a blowing exhaust. Remember, this could be anywhere, from the manifold all the way through to the tailpipe.
Otherwise, check out some of the other suggestions above.
In the end, you might decide that you just have a loud car. That’s okay! It’s better to be safe than sorry.
As always, a brief look down a page on the internet is helpful, but no match for an in-person inspection.
Take your car to a mechanic. They’ll have a thorough look for you. In the end, they might tell you everything’s fine – don’t be embarrassed! It’s their job, and it’s better to be careful than sorry.
