Did you hear that?
It sounded like rattling.
It’s highly unlikely that it’s a snake, so if your vehicle starts making rattling noises, there’s clearly a problem that needs to be addressed.
What causes a car to make a rattling sound when accelerating? The most likely culprits include the following:
- Broken Heat Shield
- Broken Machine Stand
- Valve Carriage Problem
- Transmission Problem
- Worn Exhaust Components
Fortunately, in this guide, we will explore each of the reasons above in detail. Not only that, we will also discuss how to fix it.
Let’s get started right away!
Does Your Car Vibrate When Accelerating? 5 Possible Causes And How To Fix It
Cause #1 – Damaged Heat Shield
The heat shield is a metal shield that surrounds various parts of the exhaust system, keeping your car safe from the heat it gives off.
One of the reasons heat shields tend to break is because they are close to the ground. Often around the gas tank, exhaust, exhaust pipe, and exhaust manifold. This not only exposes them to debris but also moisture, which means they are likely to have problems with rust.
You guessed it – if the damage is severe enough, it can cause your car to make a rattling sound as it accelerates.
The reason they do it while accelerating is because it puts more pressure on the engine. The harder it works, the more air flows through the exhaust, which is where most of the heat shields in your car are located.
How to fix
The good news is that unless they sustain real damage, heat shields are quick and affordable to repair. If you had to replace it, it would likely cost you between $250-$300. If not, installing it where it’s welded at a local shop will help.
Cause #2 – Broken Machine Stand
In case you didn’t already know, the average car engine weighs around 300 lbs. – and the engine mount is what holds it securely in place. They’re made of rubber and metal, so as you might expect, if they break, there’s nothing to stop them from moving.
This means metal on metal contacts, which can cause your car to make a creaking sound as it accelerates due to the added workload (as well as momentum).
Left alone, there’s likely to be more than just a toy to worry about. Some possibilities include bent or damaged exhaust manifolds, decreased handling, or drivetrain failure.
How to fix
The good news is that a broken or damaged engine mount is not difficult to fix. As long as you always can crawl under your car and check yourselfit may be easier to get a licensed professional to lift it up and have it checked.
They should be able to replace a worn/damaged stand for between $200-$500.
Cause #3 – Valve Carriage Problem
If your car makes a rattling sound that sounds like a glass bottle clinking, it’s likely a valve train problem.
This system is responsible for the operation of the intake and exhaust valves. If one of them is jammed or worn (including the hydraulic lifter), it can cause premature ignition in the combustion chamber.
This is often referred to as carbon rap, and is usually caused by dirty oil or filling your car with the wrong octane rating.
How to fix
If it’s a valve train (located at the top of the engine), the first thing you should do is check the shape of your oil. If it gets dirty, it may just need an oil change.
It is also possible that your machine requires high octane fuel, which will appear in your owner’s manual. If it is designed for a 95 and you install an 89, the performance of the engine will decrease and it may make a rattling sound.
Cause #4 – Transmission Problem
A lot happens inside a transmission, and like most engine components, if it doesn’t receive adequate lubrication, the transmission will not operate properly.
The transmission fluid forms a thin layer between the moving parts so that they do not rub against each other directly. Without enough, they will, which can cause your car to vibrate as it accelerates.
Ignoring a fluid-depleted transmission will eventually lead to expensive repair bills. When metal grinds on metal, it will cause the gears to wear out, and when they can’t be used, you have to rebuild or change transmission.
How to fix
Luckily, if you regularly change your transmission fluid every 30,000-60,000 miles, you’ll never have a problem with it. Regardless, if your tranny, the first thing you should do is check the fluid level. If it’s low, then you need to add more.
For more information on tranny fluids, as well as the costs associated with replacing them, see our previous article here.
Cause #5 – Worn Exhaust Components
There are many different components in the exhaust system that can cause your car to vibrate as it accelerates.
Some of them are:
Ignoring any of these can have disastrous effects on the rest of the system. Not only that, they can also lead to reduced performance and fuel economy.
How to fix
The first step is to find out which part of the system is experiencing the problem. You can crawl under your vehicle and check for damage, just be sure to cool it down first if you’ve been driving recently.
You can also use your hands to “shake” the system, listening for a rattling sound.
If you’re not comfortable doing it yourself, taking your car to a licensed mechanic may be your best bet. If they don’t see a visible problem, they can also do a pressure test to see if there’s a leak somewhere.
Don’t Lose the Battle of Rattle – Instead, Get Rid of It
A car rattling as it accelerates will eventually become more than just a nuisance. As you may have noticed from the causes of car crackling above, many of them stem from a lack of proper care.
For this reason, be sure to take care of your car, and if it starts to crackle, treat it before it gets worse.