7 Proven Ways to Fix Car Rattling Noise When Accelerating

Annoying rattling noises from your car when you accelerate are nerve-wracking when you don’t know if it affects the safety and drivability of your car. Whether major or minor, a rattling noise from a car as it accelerates is a sign of something seriously wrong and should not be ignored.

Fix a Car Making Rattling Noise When Accelerating

A rattling noise when accelerating often signals faulty wheel bearings. Essential for smooth wheel rotation, compromised bearings may result in shaky tires, uneven tread wear, and impaired driving safety.

A rattling noise during acceleration can stem from several issues: compromised suspension parts, misaligned driveshafts, or inadequate transmission fluid. It is also common for loose or damaged heat shields to produce rattling sounds when accelerating.

In this article, I will discuss how to find out the source of a car rattle when accelerating and how to fix it once you know where the problem lies.

Also read: Car Making Clicking Noise When Driving? Find Out Why!

Rattling Noise When Accelerating: What It Says About Your Car and How To Fix It

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Rattling Noise When Speeding Up

Your car making a rattling noise when accelerating or driving at highway speeds indicates that it might be time to take a closer look at what’s happening with your car. 

1. The Exhaust Components May Be Loose

First, it is good to rule out the simple things before considering car engine and transmission issues. A loose exhaust system will cause rattling as you accelerate when the exhaust manifold bangs on other car parts

This rattling will increase with speed and may not be heard when the car is at low speeds below 20mph (32 kph). Acceleration generates and transmits massive amounts of energy through the transmission system, which causes a car to shake. 

As the car shakes, the loose exhaust system will bang on the body and cause rattling sounds.

Other possible signs that your exhaust system is not securely attached include

  • stench of exhaust gases.

  • Loud exhaust rumbles that were previously unheard.

  • Decreased performance.

  • Increased fuel consumption.

Some things that may make the exhaust loose are

  • Bad driving conditions

  • Harsh driving habits characterized by rough acceleration

  • Improper installation of the exhaust system

Here are some tips on how to fix this problem:

  1. Inspect your exhaust system while the engine is running. Ensure the gear is not engaged. 

  2. Note if the exhaust is loose and shaky, smoke leakages, and listen for strange noises. You can grab the exhaust tip at the back and try to shake. 

If you identify the exhaust as the culprit that is causing the rattling noise when accelerating, you must secure it. You can fix the bolts and mounts yourself or engage a qualified mechanic.

For exhaust rumbles that are a sign of leakage, you need to take your car to a mech for the identification of the leakage and sealing. 

Also read: How to Temporarily Quiet Down a Loud Car Exhaust

2. Suspension Parts Are Worn Out

Suspension Parts Are Worn Out

The suspension system is crucial for a car’s ability to control its motion. It connects the car’s body to the wheels through shock absorbers, struts, stabilizer links, rods, and bushings. 

When one of these components becomes loose or wears out, you should expect a rattling noise when accelerating, considering that the suspension system absorbs the shocks that the wheels generate as they roll on the road. 

The rattling noise from your suspension system will be worse when you drive through a rough road or over bumps.

Besides the rattles, other signs of a damaged suspension system include the following:

  • A bouncy ride

  • Excessive vibrations

  • A swaying or leaning on one side

  • Uneven tire wear 

To fix this problem, get your suspension system checked by a qualified mechanic. I do not recommend doing this yourself because some of the suspension parts are in hard-to-reach places. 

For these parts to be accessed, your car has to be lifted. On top of that, some suspension wear may not be visible to the untrained eye.

Possible causes of suspension wear and tear include 

  • Poor maintenance

  • Harsh driving

  • Overloading

3. Damaged Heat Shields 

Damaged Heat Shields 

Your car has several heat shields to protect parts from excessive heat. These heat shields include 

  • thermo-protective barrier between your exhaust system and other car parts. 

  • Heat shields in the engine bay area to prevent heat damage to internal components and bodywork. 

The heat shield can break due to rust or crack, causing a rattling noise as the car accelerates. 

Other signs that your heat shields are damaged include:

  • Excessive cabin heat

  • An overheating engine

  • A burning smell from under the hood or car body

  • Decreased performance

The easiest fix is inspecting your car to identify the worn-out shield and then replacing it. 

While at it, consider insulating your entire car from heat, sound, and dust. Car deadening will make your ride more comfortable and can mute the rattling sounds.

car deadening

Some issues that may damage your heat shields include:

  • Normal wear and tear

  • Impact of collision accidents

  • Corrosion from rust

You should replace a damaged heat shield as soon as possible to reduce the risks of deadly fires and accidents when heat damages a part, such as a fuel or a brake line.

4. Worn-Out or Loose Engine Mounts

Worn-Out or Loose Engine Mounts

Your engine and transmission are mounted to the car frame through motor mounts. These mounts secure your engine and transmission to the car frame while reducing noise and vibrations. 

When a mount becomes loose or worn out, it will allow your engine or gear to move around during acceleration, and this can cause rattling sounds. As your engine shakes and moves about due to faulty mounts, it will damage other parts. 

Commonly, faulty mounts will cause the engine to incline towards one side, misaligning drive shafts. The misaligned shafts can cause a rattling noise when accelerating and bring about many other complications.

Damaged engine mounts also show additional signs. 

  • Engine vibrations

  • Oil leakages

  • Excessive damage to other engine parts

  • Misaligned wheels

Have your motor mounts checked by a qualified technician as soon as possible, and don’t try to fix the problem yourself. The mountings have some hydraulic shields that, at times, leak hydraulic fluid, which might be challenging to detect.

5. Transmission Issues

Transmission Issues

When transmission fluid gets low, your car may start making rattling sounds. Low transmission fluid can cause gears to overheat and make the sounds worse. 

Other signs of low transmission fluid include 

  • Difficulty in changing gears

  • Transmission slips

  • Car jerks as it speeds

Here are some possible causes of low transmission fluid. 

  • Transmission leaks

  • Bad driving habits

  • Poor maintenance 

How to Fix Transmission Issues Leading to Car Making Rattling Noise When Accelerating

You can fix rattling noises caused by transmission issues easily. Here are simple steps to follow to prevent your gears from overheating.

  1. Check your transmission fluid levels

  2. If the fluid is low, drain and refill with new transmission oil; topping up is not a good idea.

  3. Ensure you service your transmission regularly to lower the chances of leaks.

6. Worn-Out Wheel Bearings

Worn-Out Wheel Bearings

When your wheel bearings wear out, they may cause rattling sounds. Wheel bearings attach the wheel to the wheel hub, and when they wear out, they can make the car shake and rattle.

Other symptoms of worn-out bearings include

  • Excessive wobble 

  • Increased fuel consumption

Causes of wheel bearing wear and tear include

  • Bad driving habits

  • Collision accidents

  • Normal wear and tear

To address this issue, get a qualified mechanic to check your wheel bearings and advice accordingly. 

7. Valve Train and Rattling Noise

The valve train is a crucial component of an engine’s internal system, responsible for the operation of the intake and exhaust valves. It includes parts like the camshaft, lifters, pushrods, rocker arms, and valves.

Causes of Rattling Noise in the Valve Train

  • Worn or Damaged Lifters: Hydraulic lifters can wear out or get damaged over time. When they do, they might not maintain proper contact with the camshaft, leading to a tapping or rattling noise, especially during acceleration.
  • Loose Rocker Arms: The rocker arms, which help open and close the valves, can become loose. This can result in a distinct tapping sound that intensifies with acceleration.
  • Valve Clearance Issues: Over time, the clearance between the rocker arms and the valve stem can change. If the clearance becomes too large (often due to wear), it can cause a rattling or ticking noise. This is often referred to as “valve clatter.”
  • Worn or Damaged Camshaft Lobes: The camshaft has lobes that control the opening and closing of the valves. If these lobes wear down or get damaged, they can’t effectively control the valve movement, leading to noises.
  • Timing Chain Issues: While not directly a part of the valve train, the timing chain (or timing belt in some vehicles) plays a crucial role in synchronizing the camshaft’s movement with the crankshaft. If the timing chain becomes loose or worn, it can produce a rattling sound, especially during acceleration.

Addressing the Issue

If you suspect a problem with the valve train, it’s essential to address it promptly. Ignoring such issues can lead to decreased engine performance, reduced fuel efficiency, and potential long-term damage to the engine.

It’s advisable to consult a professional mechanic to diagnose and fix valve train-related problems accurately.

Preventive Maintenance

Preventive Car Maintenance

Regular Maintenance Checks

Regularly inspecting your vehicle can help identify potential issues before they escalate. This includes checking the exhaust system, suspension parts, heat shields, engine mounts, transmission fluid levels, and wheel bearings. By addressing minor issues promptly, you can prevent more significant problems and costly repairs in the future.

Recommended Driving Habits

Avoiding harsh accelerations and decelerations, not overloading your vehicle, and being cautious on rough terrains can reduce the wear and tear on your car’s components, minimizing the chances of rattling noises.

Prompt Issue Addressing

Ignoring minor rattles can lead to more severe problems. Addressing issues as soon as they arise ensures the longevity and efficiency of your vehicle.

Using Diagnostic Tools

On-Board Diagnostics II (OBD-II) scanner

With the advancement of automotive technology, diagnostic tools have become an indispensable part of car maintenance and repair.

These tools, especially the On-Board Diagnostics II (OBD-II) scanners, interface with a car’s computer system to monitor the performance of the engine and other essential systems.

Benefits

  • Accuracy: These tools can pinpoint issues by providing error codes, making the diagnostic process more precise.

  • Time-saving: Instead of manually inspecting each component, mechanics can quickly identify and address the root cause of a problem.

  • Cost-effective: By accurately diagnosing issues, car owners can avoid unnecessary repairs and replacements.

Limitations

While OBD-II scanners provide valuable insights, they might not capture every issue, especially those related to non-electronic components. It’s essential to combine these tools with manual inspections for a comprehensive assessment.

Professional Mechanic vs. DIY

Preventive Maintenance

When to DIY

  • Simple Repairs: Tasks like changing the oil, replacing air filters, or tightening loose components can often be done at home with basic tools and knowledge.

  • Cost Considerations: DIY can save on labor costs, making it an attractive option for minor repairs.

When to Consult a Professional

  • Complex Repairs: Issues related to the transmission, engine internals, or electronic systems usually require specialized tools and expertise.

  • Safety: Some repairs, if done incorrectly, can compromise the vehicle’s safety. It’s crucial to recognize when a task is beyond one’s skill level.

  • Warranty: DIY repairs might void a car’s warranty. Always check warranty terms before attempting any repair.

Also read: Brake Squeak At Low Speeds

Cost Estimates

Cost Estimates

Repair costs can vary based on the issue and the vehicle’s make and model. Here’s a rough estimate:

  • Loose Exhaust System: $100 – $500

  • Worn-Out Suspension Parts: $250 – $1,500

  • Damaged Heat Shields: $50 – $200

  • Engine Mounts: $250 – $800

  • Transmission Issues: $150 – $1,000

  • Wheel Bearings: $300 – $1,000

Environmental Impact

Environmental Impact

Emissions and Pollutants

A malfunctioning car, especially one with exhaust or engine issues, can release harmful pollutants into the environment. These pollutants can contribute to smog, acid rain, and respiratory problems in humans.

Fuel Efficiency

Cars running inefficiently due to unresolved issues can consume more fuel, leading to increased carbon dioxide emissions and higher fuel costs for the owner.

Waste

DIY repairs, if not done correctly, can lead to more frequent part replacements, contributing to increased waste in landfills.

Warranty Considerations

Before addressing any issue, it’s essential to check if your car is still under the manufacturer’s warranty or an extended warranty. Some issues might be covered, saving you repair costs.

Safety Concerns

Safety Concerns

Driving Risks

A car making rattling noises or showing signs of malfunction can pose significant risks on the road. For instance, worn-out wheel bearings can lead to unstable driving, especially at high speeds.

Potential for Accidents

Ignoring issues like brake problems or steering malfunctions can lead to accidents, endangering the driver, passengers, and others on the road.

Long-term Damage

Prolonged neglect of minor issues can lead to more significant problems. For example, a small leak in the exhaust system, if ignored, can lead to more extensive damage, affecting the car’s overall performance and safety.

Final Thoughts

Your car rattling when accelerating is a sign of serious issues with the internal components. Ignoring car rattles can put you at risk for some causes of rattling sounds are serious mechanical issues. 

Check your car or get it checked by a qualified technician and address the cause of the rattling urgently. The rattles can lead to something more serious and increase repair costs.

Also read: How to Stop Car Door Rattling From Speakers and Sub

Frequently Asked Questions

What is the rattling sound under my car when I accelerate at low speed?

The rattling sound under your car when accelerating at low speed could be due to multiple reasons. It might be related to a loose heat shield, worn-out suspension components, or even a faulty exhaust system. It’s recommended to have a professional mechanic inspect your car to determine the exact cause.

Can rattling noise be the transmission?

Yes, a rattling noise can be related to the transmission. A poorly lubricated or malfunctioning transmission can lead to metal components vibrating or grinding against each other, causing a rattling sound when you accelerate. It’s advisable to have a professional mechanic inspect your transmission if you suspect it’s the source of the noise.

Why does my car rattle when I move?

If your car rattles when you move, there could be several reasons. It might be due to loose or damaged components in the exhaust system, worn-out suspension parts, or issues with the wheel bearings. Additionally, problems with the transmission or engine can also cause rattling sounds. Proper diagnosis by a mechanic is necessary to pinpoint the exact cause.

When I press the gas, my car makes a noise?

When pressing the gas pedal results in noise, it can indicate various issues. If the noise is a rattling sound, it could be related to the exhaust system, transmission, or engine components. Squealing or whining noises might point to problems with belts, pulleys, or the power steering system. A professional inspection is recommended to determine the source of the noise.

How do I fix the rattling noise under my car?

Fixing a rattling noise under your car requires identifying the root cause first. If it’s due to a loose heat shield, securing it back in place can solve the issue. For issues related to the exhaust system, suspension, or transmission, a professional mechanic should inspect and repair the components accordingly. It’s essential to address the underlying problem to prevent further damage.

Is a rattling noise during acceleration dangerous?

While a rattling noise itself might not be immediately dangerous, it could indicate underlying issues that, if left untreated, might lead to more significant problems and potential safety hazards. It’s recommended to address any unusual noises promptly by having your car inspected by a professional mechanic.

Can I fix a rattling noise in my car by myself?

Depending on your experience and knowledge of car mechanics, you might be able to address simple issues that cause rattling noises, such as securing loose components. However, for more complex problems involving the engine, transmission, or suspension, it’s advisable to seek the expertise of a qualified mechanic to ensure proper diagnosis and repair.

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