Car Making Rattling Noise When Accelerating: Cause and Fixes

If you want to know why your car makes rattling noise when accelerating, we have plenty of answers.

For example, it could be an issue with the exhaust or low lubricant. In this article, we provide all the causes along with tips to diagnose the rattling part and repair methods.

Why Does the Car Make a Rattling Noise When Accelerating?

The car makes a rattling noise when accelerating because of a problem with the exhaust components. The noise from the front end can be due to faulty engine parts or accessories. Poor engine and transmission lubrication or loosened fittings can also cause car parts to rattle.

– Heat Shield Rattling Sound When Accelerating at Low Speed

Almost all exhaust parts have high temperatures, so heat shields prevent the heating of other car parts. The shield gets damaged due to some reasons and creates rattling noises.

The shield is a thin metal, covering all exhaust elements that come in contact with other car systems. When the shield breaks or damages, it creates noise because it hangs loose and collides with other parts. Moreover, if there is a hole or crack in the shield, it will also be noisy when you accelerate.

There are different reasons why the heat shield breaks, but some of them are as follows:

• The metallic shield wears out due to rust. There is a higher risk of rust if exposed to moisture or debris, but it can also happen over time.
• Whenever you drive your car, each part undergoes vibrations. Over time these parts get loose and displace a little. When these parts collide with the shield, it breaks.
• A car accident can also damage the shield. If it undergoes great impact, the shield may detach from one end and start hanging from the other. It can produce car rattling sounds.

– Rattling Noise Coming From Exhaust Parts

Apart from the heat shield, other exhaust parts can develop defects and cause rattling noises. These include exhaust pipes, manifolds, mufflers, hangers, catalytic converters, and other parts.

If you have recently had an accident, the exhaust pipe may break or hang from one end. Moreover, it expands and contracts due to overheating which can leave cracks. These problems lead to noise when you drive, especially when you go over bumps.

A leakage in the exhaust can be a result of a blown gasket. The gasket connects the manifold to the engine, so if it breaks due to corrosion or any other reason, you will notice noise and leakage.

The muffler silences the noises from the exhaust, but if it gets damaged you will have the answer to “Why is my car making a rattling noise when I accelerate?” This component experiences high pressures and temperatures that can be damaging. As a result, it loses its function of reducing the noise.

The exhaust system also has clamps and hangers that hold all parts in their place. These hangers get loose over time due to vibrations or impact, or they may corrode due to moisture and salt. Non-OEM hangers or clamps will also produce noise because they do not fit well.

Similarly, a bad catalytic converter can cause rattling. It is present in most latest car models and helps convert harmful exhaust gasses into non-toxic compounds. Overheating can break parts of the converter that move around and create noises.

If the sound is coming from any exhaust part, there is always an underlying cause that needs to be addressed. These causes can have a bad impact on the performance of your car, so you should fix them fast.

– Car Transmission Rattling Noise When Accelerating

The transmission works smoothly thanks to the fluid that lubricates all components. These parts are always moving when you drive, so the fluid acts as a protective film to prevent them from rattling. Insufficient fluid creates metallic clattering noises.

If you drive the car even after you hear these noises, the transmission parts will slowly fail. Thus, you should diagnose and repair it before it is too late.

– Front End Rattle When Accelerating Due to Engine Accessories

When we hear about issues in the engine we imagine costly repair and severe damages, but it is not always true. In some cases, the rattling noise can be a result of faulty engine accessories.

For example, the belt pulleys act as accessories to the engine. They drive the belt, but when they wear out, you hear rattling. If you suspect the belt, confirm the issue by temporarily removing it, starting the car, and revving the engine to see if the noise continues.

If you are thinking, “Why is my car making a rattling noise in the front?” you probably have worn engine mounts. These mounts hold the engine in its place, but if they wear out, they are unable to keep the parts in their position.

These rubber and metal motor mounts can damage due to overloading, oil leakage, or extreme temperatures. The noises are more prominent when you press the gas pedal and accelerate.

– Issues With the Internal Engine Cause Rattling

Problems with the internal engine or valve train are more serious. You might hear a piston slap, knocking rod sound, or noise from the lifter. Defects in the timing belt also lead to similar troubles.

A piston noise is normal when you start driving, but there must be an underlying cause if it persists. Pistons inside the engine function by moving vertically inside the cylinder.

The metallic pistons contract and expand depending on the engine. The engine is still cold when you start the car, so the contracted pistons move around and rattle inside the cylinder. The noise silences once the engine gets hot and if everything is normal.

If the slap does not stop and you notice a loss of oil or colored exhaust gas, you might have a worn piston or connecting rod. Since pistons expand and contract, they weaken over time and break, allowing the oil inside the cylinder. Consequently, you will hear noises from the engine.

A timing belt keeps other parts functioning smoothly, such as the water pump. A belt tensioner provides the necessary tension to the belt so it remains centered. Any defect in the tensioner loosens the belt and results in rattling.

The chain tensioner may damage due to

• Improper adjustment leads to over or under-tensioning of the belt
• Normal wear of springs and bearings due to aging
• High temperatures or contamination
• Misaligned engine accessories

You can detect a problem with the belt or tensioner by following these steps:

• Remove the belt cover and other accessories to look for signs of cracks or fraying.
• Align the marks on the camshaft and crankshaft by turning the bolt.
• Press the timing chain with your finger. It should be firm and should not move more than a half inch.
• If it is loose, inspect the tensioner and notice any leaks or cracks.

You shouldn’t drive further if you start hearing these noises. Stop the car and observe the engine bay. Although the repair is expensive, get your car fixed to avoid serious life and car damage.

Worn spark plugs are another reason for the metal rattling sound when driving. You can detect it if the engine misfires. It also rattles if it is loose due to vibrations.

– Low Engine Oil Causes Metal Rattling

Low motor oil also causes a metal rattling noise when accelerating. You would know the importance of lubrication for the proper function of car parts. A lack of it can result in friction between metallic or solid parts and hence rattling.

Although it does not seem like a grave problem, low lubricant levels can badly affect your car’s performance over the long run. Check the oil level by using a dipstick and insert it into the tank.

If the oil level is below the minimum mark, fill the tank. Moreover, if the oil is dark, it should be changed. Contaminated oil appears dark and fails to lubricate the engine as efficiently as clean oil.

– Noise From Loose Internal or External Car Parts

Any loose or misfitted parts in the car would rattle when not mounted in their place. It may include steering or suspension components, glove compartments, etc.

The car suspension ensures a smooth and comfortable ride, but a loose part can create noise. The shocks, struts, or bushings can get loose because of an accident or vibrations. You can detect the defects in these parts by pressing on them or noticing any play.

Some interior car units can also rattle if they are not the right size or damaged. For example, the door of the glove compartment might not fit properly and create noise. Similarly, the doors of window regulators or latch assemblies can be noisy.

How To Fix a Car Making Rattling Noises When Accelerating?

To fix a car making a rattling noise when accelerating, you can mend the heat shield or exhaust parts using epoxy. You can also top up the low engine and transmission lubricants for smooth functions. Replacing the worn engine mounts and valvetrain parts can stop the rattling.

– Repair or Replace a Loose Heat Shield

The repair of the heat shield depends on the severity of the damage. If you wonder, “How do I fix a rattling noise when I accelerate without spending money?” you can repair the heat shield yourself if it is not completely corroded.

You can either take the car to the mechanic and get the shield spot welded or follow the steps below:

1. Observe the shield to pinpoint the damaged spot. You can look for cracks or rusty areas.
2. In case of rust, you can use sandpaper or a wire brush to scrub off the rusty particles.
3. After removing the rust, the damaged part will be visible.
4. Fix it by using an adhesive or epoxy that resists high temperatures.
5. You can buy a good quality epoxy resin from the hardware store and follow the steps mentioned in the packaging.
6. Allow it to dry for hours or a day (as stated in the instructions).
7. If the shield is hanging from an end, secure it with the help of a tape or clip. Use heat-resistant tape to fix the loose exhaust heat shields to the exhaust.

However, if the whole shield corrodes, get it replaced by a mechanic.

– Fix the Rattling Engine Components

If you diagnose defective engine mounts, you do not have to worry about the repair cost. It is better to hire a mechanic because it requires car lifting. A mechanic does not charge much to replace the mounts.

If there are low engine oil levels, you can fill the tank to the required oil pressure and stop the rattling.

Moreover, you can change the oil if it looks dark. It will improve the engine performance and fix the noises.

Contrarily, a problem with valve train parts is difficult to fix. The replacement of worn parts is expensive. In some cases, the engine needs reassembling, so these processes need professional help.

– Fill up the Transmission Fluid To Stop Rattling

Filling up the transmission fluid can solve your problem. You should buy suitable fluid depending on your car. You can consult the owner manual to get an idea and then look for the particular type in the market.

Depending on the required quantity, you can buy it for $5 to $20. Labor costs for changing or filling the fluid can be much higher, so you can do it yourself if you have expertise.

– Fix the Rattling Exhaust Parts

There are many exhaust parts, and any of them can fail and create noise. Once you diagnose the faulty part, you need to analyze the severity of the damage. You can mend it using heated epoxy if there is only a small hole or crack.

Acute damages, for example, large rusty patches or holes, show the need to replace the entire component. The cost of repair will also depend on the severity of the issue.

Conclusion

Now you are familiar with why cars make rattling noise when accelerating causes and fixes.

Keep the following points in mind to solve this problem:

• Front-end rattling is linked to loose or damaged engine parts or accessories.
• Hanging exhaust units, loose interior elements, and poor lubrication cause rattle.
• Fix the loosened parts with epoxy or replace defective parts to stop the noise.

Use these findings to get rid of the annoying car rattle and enjoy your ride.