If your car rattles when accelerating, don’t worry – you’re not alone. This is a common problem that many drivers experience. There are several causes of this issue; fortunately, there are also several fixes.
There are several reasons why your car might rattle when you accelerate. It could be something as simple as a loose heat shield or exhaust component or something more serious like bad catalytic or damaged pistons.
In this blog post, we will discuss the most common causes of car rattling when accelerating, as well as the best ways to fix them. Keep reading to learn more!
Table of Contents
What is the Rattling Noise Coming From Your Car?
Rattling noise can sound like many things depending on what is causing the noise. It can sound like metal against metal, glass against glass, or even something soft like fabric against the fabric. Sometimes, it can be hard to pinpoint the source of the rattling noise.
However, it is usually caused by loose objects inside the vehicle that are banging around as the car moves. This can be anything from a loose screw to a piece of trim that has come loose.
Rattling noise from your car can be very annoying and even cause you to worry about the condition of your vehicle. Many things can cause a rattling noise. But largely, if we were to list the major causes of rattling noise, they would be:
- Issues Related to Engine
- Exhaust System Problems
- Transmission Defects
- Loose Interior or Exterior Components
Any other cause would be a sub-classification of these issues here.
Causes of Rattling Noise When Accelerating
Now that we know what rattling noise is let us look at some of the most common causes of this problem.
- Bad Engine Mounts
- Broken Heat Shield
- Running With Low or No Engine Oil
- Overstretched Timing Belt
- Worn Piston Rings
- Bad Catalytic Converter in Exhaust System
- Broken Flywheel or Flexplate Teeth
- Worn Timing Belt Pulleys and Tensioners
- Loose Interior Trim
- Weak Water Pump
- Corroded Exhaust Components
- Bad Rocker Arms
Let us describe each of these in detail.
1. Bad Engine Mounts:
The engine mounts play a crucial role in the function of your car. They keep the engine secure and prevent it from vibrating excessively. However, over time they can become worn out or damaged, which can lead to various problems.
One of the most common issues is a rattling noise from under the hood. When mounts have gone bad, they allow the engine to move around freely, which can cause all sorts of banging and rattling noises.
2. Broken Heat Shield:
A heat shield is a metal or composite piece designed to protect other parts of the car from excessive heat. They are typically found around the exhaust system.
Heat shields can become damaged or broken over time, leading to rattling noises. If you suspect that your heat shield is the source of the noise, you should have it inspected by a professional as soon as possible.
3. Running With Low or No Engine Oil:
One of the most common causes of engine problems is running low or out of oil. Engine oil is necessary for lubricating the moving parts in your engine. When the oil pressure is low, there is not enough oil to properly lubricate the engine.
Now, all the components in the engine start to rub against each other, which can cause a rattling noise to emanate from under the hood.
4. Overstretched Timing Belt:
If the timing belt is worn, it can cause a rattling noise. The timing belt is responsible for keeping the engine’s valves in sync with the pistons. If the timing belt is worn, it can slip and cause the valves to open and close at the wrong time. This can cause rattling noises.
On the other hand, if the timing belt is worn, it can become overstretched. When this happens, it can cause the pulleys that the timing belt runs on to become misaligned. This can also cause a rattling noise when you increase the engine speed.
5. Worn Piston Rings:
Piston rings are a set of metal rings fitted into the grooves on the outer edge of a piston in an engine. The primary purpose of these rings is to help seal the combustion chamber so that the pressure created by the burning fuel is not allowed to escape.
In addition, the rings also play a role in keeping oil from entering the combustion chamber and help to maintain proper lubrication between the piston and cylinder wall.
Over time, however, these rings can become worn down, which can cause several problems. One of the most common is termed piston slap. This is when the rings no longer fit snugly against the piston, which causes them to move around and make a loud rattling noise.
6. Bad Catalytic Converter in Exhaust System:
The catalytic converter is a device located in a car’s exhaust system. Its purpose is to convert harmful gases into less harmful ones before they are released into the atmosphere.
However, over time the catalytic converter can become clogged with soot and other debris. When this happens, it can cause the engine to run lean, leading to a knocking or rattling noise.
Another problem that can occur with the catalytic converter is called thermal shock. This is when the converter becomes overheated. If this happens, you will hear a loud banging noise from under the hood as well as see flames and smoke coming from the exhaust pipe.
7. Broken Flywheel or Flexplate Teeth:
The flywheel or flexplate is a metal disc attached to the back of the engine. It is responsible for transferring power from the engine to the transmission.
Another purpose of the flywheel is to keep the engine’s crankshaft from moving back and forth as the pistons fire during the power stroke. It does this by providing a surface for the clutch discs to grip when the engine is running.
If the flywheel or flexplate becomes damaged, it can cause a rattling noise. This is because the damaged surface will no longer be able to provide a smooth surface for the clutch discs to grip. The result will be a rough, uneven surface that will cause the discs to chatter.
In some cases, the teeth on the flywheel or flexplate can become damaged. These teeth are responsible for meshing with the starter motor, so if they are damaged, the starter will not be able to engage properly. But it will also cause a rattling noise.
One other reason why the transmission of a car makes rattling noises would be running on low transmission fluid.
8. Worn Timing Belt Pulleys and Tensioners:
The timing belt pulleys and tensioners serve a slightly different purpose. The pulley keeps the timing belt in place while the tensioner ensures the proper amount of tension on the belt. Over time, however, these parts can become worn and cause a rattling noise.
In particular, the bearings in the pulleys can wear out, which will cause them to make a noise as they spin. Additionally, the teeth on the pulleys can also become damaged, which will cause a rattling noise.
As with the timing chain tensioner, it can also become worn and no longer provide the proper amount of tension. As a result, the timing belt will begin to slip, which will cause a rattling noise.
9. Loose Interior Trim
Interior trim is a trim that covers the interior of a vehicle. It protects the interior from dirt, water, and other elements. Loose interior trim can cause a rattling noise because it is not securely fastened to the vehicle’s frame.
This can be caused by several things, including poor installation, wear, and tear, or an accident. In some cases, a loose interior trim may just need to be tightened up.
However, if the rattling noise is caused by something more serious, such as damage to the vehicle’s frame, it will need to be repaired.
10. Weak Water Pump:
The water pump is responsible for circulating coolant through the engine. Over time, however, the bearings in the water pump can become worn and cause a rattling noise.
Additionally, the impeller (the part of the water pump that pushes the coolant) can also become damaged and cause a rattling noise. If this happens, it will need to be replaced.
11. Corroded Exhaust Components:
An exhaust system is a set of components in a vehicle that helps to move the exhaust gases away from the engine. It usually consists of an exhaust manifold, catalytic converter, and muffler. The main function of the exhaust system is to reduce noise and emissions.
Corrosion is a common issue with exhaust systems. Over time, the metals in the system can start to break down and wear away due to exposure to the elements. This can cause a rattling noise when the car is running.
In some cases, the corrosion can be so severe that it causes holes to form in the exhaust pipes. Exhaust system corrosion is not something that should be ignored, as it can eventually lead to serious problems. If left unchecked, it could even cause your car to fail its emissions test.
12. Bad Rocker Arms:
If your car’s rocker arms are making a rattling noise, it could be due to a few different things. The most common reason is that the pushrods are not properly lubricated.
This can cause the metal to grind against each other, and over time, this will wear down the surfaces of the pushrods and rocker arms. This will eventually lead to a loss of power and efficiency in your engine.
Another possibility is that the rocker arms themselves are worn out. This is less common, but it can happen if you drive your car hard or don’t maintain it properly. If this is the case, you’ll need to replace the rocker’s arms.
Other valve train components can also cause a rattling noise. If your car has hydraulic lifters, they may need to be adjusted or replaced. The timing chain could also be the culprit. If it’s loose, it can cause the valves to open and close at the wrong time, creating a rattling noise.
How to Fix Rattling Noise When Accelerating?
Once you’ve determined what is causing the rattling noise, you can begin troubleshooting the problem. Here are a few ways to fix a rattling noise when accelerating:
1. Pouring Fresh Engine Oil:
If your car is low on oil, it can cause a rattling noise. The best way to fix this is to simply pour fresh engine oil into the engine. This will lubricate the moving parts and should stop the noise.
You can check your car’s oil level by opening the hood and locating the dipstick. The oil level should be between the “full” and “low” marks on the dipstick. If it’s below the “low” mark, you’ll need to add more oil. Be sure to buy the correct type of oil for your car.
Once you have the oil, open the hood, locate the oil fill cap, and pour in the new oil until the dipstick reads “full.” Then, start your car and listen to the rattling noise. If it’s still there, move on to the next troubleshooting step.
2. Replacing Engine Mounts:
If your car’s engine mounts are worn out, it can cause a rattling noise. You’ll need to have them replaced. This is a fairly simple process that most mechanics can do.
To replace the engine mounts, first, locate the mount causing the problem. Then, remove the old mount and install the new one. Be sure to use new nuts and bolts when installing the new mount.
The replacement cost of an engine mount will vary depending on the make and model of your car. However, most mounts cost between $150 and $350.
3. Replacing Heat Shields:
If your car’s heat shields are damaged, they can cause a rattling noise. The best way to fix this is to replace the damaged heat shields with new ones.
Fortunately, replacing a cracked heat shield is not difficult. In most cases, all you need is a new heat shield and some basic tools. Here is a step-by-step guide on how to replace a heat shield:
1. Remove the old heat shield. This will usually involve removing some bolts or screws. Be sure to keep track of all the hardware so you can reuse it later.
2. Clean the area where the heat shield was mounted. This will help ensure that the new heat shield will have a good surface to adhere to.
3. Place the new heat shield in position and secure it with the bolts or screws you removed earlier.
4. That’s it! You’ve successfully replaced your cracked heat shield.
4. Replacing Timing Chain, Belt, Pulleys, or Tensioner:
If your car’s timing chain, belt, pulleys, or tensioner is damaged, it can cause a rattling noise. The best way to fix this is to replace the damaged component with a new one.
This is a fairly simple process that most mechanics can do. However, if you’re not comfortable doing it yourself, you can always take it to a mechanic.
The replacement cost of a timing chain, belt, pulley, or tensioner will vary depending on the make and model of your car. However, most components cost between $100 and $300.
5. Replacing Valve Train Components:
If your valve train components are making a rattling noise, there are a few things you can do to fix the problem. First, check to see if any parts are loose or damaged.
If so, replace or repair them as necessary. If the problem persists, you may need to adjust the clearance between the parts. If all else fails, you may need to replace the entire valve train.
6. Replacing Flywheel or Flexplate:
If your car has a manual transmission, the flywheel may be causing the rattling noise. To fix this, you will need to remove the transmission and take apart the flywheel or flexplate. Inspect both for damage and replace if necessary.
Replacing a flywheel or flexplate is not a difficult task, but it is best left to a professional mechanic. The replacement cost will vary depending on the make and model of your car. Expect to pay around $300 for a new flywheel or flexplate.
7. Repairing Interior Trim:
Interior trim can become worn or damaged over time, but there are a few ways to repair it. Depending on the severity of the damage, you may be able to use a putty knife and some wood filler to fill in any cracks or holes.
For more severe damage, you may need to replace the trim altogether. If you’re not sure how to proceed, it’s always best to consult with a professional before attempting any repairs.
8. Cleaning Catalytic Converter:
A dirty or clogged catalytic converter can cause a rattling noise. The best way to clean it is to remove and clean it. Removing a catalytic converter can be a difficult and expensive process. If your catalytic converter is not functioning properly, it may be necessary to replace it.
However, there are some ways that you can clean your catalytic converter without removing it. One way to clean your catalytic converter is to use a commercial cleaner. These cleaners are designed to remove deposits from the catalyst material.
Another way to clean your catalytic converter is to remove the exhaust system and access the converter directly. You can then use a brush or compressed air to remove any deposits on the surface of the converter.
If neither of these methods is effective, you may need to replace your catalytic converter. This is a more expensive option, but it will ensure that your vehicle is running properly.
There are various reasons why your car might rattle when accelerating. However, most of the time, the problem can be fixed relatively easily. In some cases, you may need to replace a component or two, but in other cases, a simple cleaning will do the trick.
If you’re unsure of what to do, it’s always best to consult with a professional mechanic. They will be able to diagnose the problem and recommend the best course of action. Thanks for reading! We hope this article was helpful.
Frequently Asked Questions
Is rattling sound something to worry about? Can you drive with it?
Rattling sounds can be worrying, especially if you’re unsure what’s causing them. However, a little investigation will reveal that the noise source is nothing to worry about.
If the rattling noises are coming from your engine bay, it could be a loose heat shield or a loose exhaust system component. These are usually easy to fix and shouldn’t cause any issues.
If the noise comes from your suspension, it could be due to a loose part or worn bushing. Again, these are usually easy to fix and shouldn’t pose any danger to you or your vehicle.
However, if the rattling sound is accompanied by other symptoms, such as strange noises from your brakes or steering. In that case, it’s best to have your vehicle inspected by a professional as soon as possible.
What other sounds does a car’s engine make when accelerating?
Some car engines may make a whining noise when accelerating. This could be caused by a failing power steering pump, which would need to be replaced.
Another potential cause of a whining noise when accelerating could be a problem with the transmission, such as low fluid levels or worn-out gears.