Reasons Behind the Rattling Under Your Car When Going Over Bumps

No one wants to experience the panic of hearing a rattling noise under your car, especially when you’re driving over bumps. However, this rattling noise doesn’t always mean something is severely wrong with your vehicle, so don’t panic immediately.

Rattling under your car when going over bumps is likely due to damaged suspension struts or control arms. It can also be due to loose parts in the exhaust system, low transmission fluid levels, worn anti-roll bar drop links, or a broken string. Additionally, check for loose items in the cabin.

The rest of this article will cover seven reasons you might be hearing a rattling noise when driving over bumps and how to fix each problem. Let’s get started!

1. The Suspension Struts Are Damaged

The suspension struts on your vehicle are critical — they’re a structural component that connects your car to the wheels. Therefore, if your suspension struts are damaged, you risk further damage to your vehicle and injury to yourself, as the struts are crucial for steering properly.

Some signs that your suspension struts are worn or damaged include:

  • Rattling sound when going over bumps
  • Rolling or swaying when cornering
  • Vibration in the steering wheel
  • Nose dive when braking
  • Uneven tire wear

If you suspect your suspension struts are damaged, you must take your car to the mechanic as soon as possible. A mechanic will have to replace your struts, as you can’t really repair them.

Unfortunately, even if only one strut is particularly damaged (because you hit a huge pothole), you’ll have to replace both, as they come in pairs. This will likely cost you a pretty penny, but it’s necessary if you want to keep driving your car.

2. The Control Arms Are Damaged

The control arm on a car goes hand-in-hand with the suspension struts — both work to allow you to successfully steer the vehicle.

While the suspension struts connect the car’s body to the wheels, the control arms are located at the front axle and only control the front two wheels. The overall shape of the control arms will differ depending on the car, but they all serve the same purpose.

Along with a rattling sound, damaged control arms show the following symptoms:

  • Vehicle vibration
  • Braking fluctuations
  • Uneven tire tread
  • Wobbly wheels

Like with damaged suspension struts, a damaged control arm will need to be replaced by a mechanic. While you can drive with a damaged control arm for a short time, it’s best to get it replaced as soon as possible to risk further damage to your vehicle.

However, there are three types of damage you can see with a control arm: ball joint, frame, or bushing damage. The exact kind of damage your car has will most likely determine how much it will cost to repair and if you need the control arm replaced completely.

3. There Are Loose Parts in the Exhaust System

A common reason you might hear a rattling sound when going over bumps is because of loose parts in the exhaust system, particularly a loose heat shield. The heat shield’s function for your car is to dissipate the heat produced by the engine — therefore, helping your engine cool down.

If your heat shield is loose, you’ll hear a rattling or scraping sound due to the shield vibrating while you drive. Luckily, this is often something you can fix yourself.

It’s imperative to fix a loose heat shield, as your car’s engine relies on the shield to keep it from overheating.

To check if your heat shield is loose, crawl under your car and look at it. However, take precautions when going under your vehicle — it’s best to have someone with you.

Most of the time, you can simply tighten the hardware securing the shield to your car. However, if the shield looks like it’s deteriorating, you might have to replace it.

4. The Transmission Has Low Fluid Levels

Low transmission fluid levels often produce a “whining” sound, which can be mistaken for rattling — especially when going over bumps.

However, if this is the problem with your car, you’ll likely hear the rattling, whining noise even when you’re not driving over bumps. Luckily, fixing low fluid levels in the transmission won’t cost you too much money, and it’s something you can easily do yourself if that’s what you want to do.

Before adding new transmission fluid, you first need to ensure that’s the cause of the whining, as multiple things could be wrong with the transmission and require more extensive repair. For instance, the problem could be as severe as needing an actual transmission repair to as simple as replacing the filter.

If you don’t know anything about car repair, you might need to take your car to a mechanic just to get it diagnosed. But, if the problem is that you need a new filter or to add fluid, that’s something you could do yourself so you don’t have to pay a mechanic.

5. The Anti-Roll Bar Drop Links Have Snapped

Like the struts and control arms, a drop link assists with steering the car. The drop link connects the end of the anti-roll bar to the control arm, ensuring that the vehicle stays stabilized, especially on turns.

Therefore, the anti-roll bar drop links are essential to operating the vehicle.

If the anti-roll bar drop links have snapped or are too worn, they can produce a rattling or thumping sound. Additionally, you might feel a “knock” on the steering wheel and find that steering and making turns is more difficult than usual.

If you suspect that this is the cause of the rattling noise in your car, it’s best to avoid driving it until you can get it fixed. However, if you have to drive it, ensure you drive slower than usual, especially when making turns.

If you have broken anti-roll bar drop links, you must get them replaced. Luckily, the cost of the materials isn’t too expensive. However, if you don’t know how to replace the parts yourself, you’ll have to pay a mechanic for labor.

You should also have your anti-roll bar links, and suspension struts checked regularly.

6. There’s a Broken Coil Spring

Coil springs support the vehicle’s weight while absorbing impacts to keep the wheels on the road. Therefore, they’re essential to the vehicle’s control system.

Unfortunately, broken coil springs are a common issue due to potholes in the road. When you hit a pothole, you risk damaging the coil springs. A lot of the time, you might not even notice anything is wrong. However, a broken coil spring can impact the wheel alignment, causing a rattling noise.

There are a few other symptoms you might have, along with a rattling noise, to signify a broken coil spring:

  • Uneven tire tread wear
  • Lower ride height — the rear of the car may sit lower than the front
  • Loud, clunking sounds accompany the rattling sounds

To fix the rattling sound due to a broken coil spring, you’ll have to get the coil spring replaced by a mechanic or yourself. It’s essential to replace the spring as soon as possible, as it can cause damage to other parts of the car if you go over a bump.

Unfortunately, a coil spring is usually pretty pricey, so you can expect to pay a good amount to replace it.

7. You Have Loose Objects in the Cabin

Lastly, you could simply have loose objects in your car’s cabin. This means various objects on the floor, in the door pockets, or in the glove compartment that aren’t properly stored could easily rattle and move around — causing you to think something more serious is wrong with your car when driving over bumps.

This is especially true with loose change, as coins clanging together can make a worrying rattling noise. However, if you’re not someone with many loose items in your car to begin with, this likely isn’t the cause of the rattling.

To see if this is the cause of the rattling noise in your car, you need to deep clean it and find any objects that could be the reason for the sound. Then, store the items properly or remove them from your car.

Next time you drive over bumps, listen for the sound. If the sound is still there, it’s best to take your car to a mechanic to get it looked at.

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Final Thoughts

A rattling sound when going over bumps isn’t always something to panic over, but it shouldn’t be ignored entirely, either. If you hear a rattling sound coming from your car, you should figure out what the problem is to ensure it’s nothing serious.

If you’re like most people, the best thing you can do is take your car to a mechanic to diagnose the problem. But, if you’re knowledgeable about cars, you can always check to see if you can fix the problem yourself.

However, always take extreme precautions when working on a vehicle.


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