What Is That Worrisome Rattling You Hear While Driving?
September 20, 2023
With thousands of interworking parts, you can expect your car to make all kinds of sounds during normal operation. But if you started driving this morning and wondered, "What is that rattling sound in my car?", chances are it's not a welcome addition to your vehicle's symphony of sounds. The problem is, that rattling noise while driving your car could be caused by a lot of different issues. From small problems with simple fixes to complete engine overhauls, you won't know what's wrong until you find the source of the loud rattling beneath your car, under your hood, or inside the cabin. Keep reading to learn the most common reasons your car makes a rattling noise while you drive and what you can do about it.
Loud Rattling Noise Under Car
Exhaust System
If the rattling noise you're hearing is coming from underneath the car while you drive, there's a good chance it's related to the exhaust system. The exhaust system spans the length of your car from the engine to the tailpipe. It's also the lowest-hanging part of your undercarriage. That means the rattling sound could be the result of road impacts or something else internally.
One of the most common sources of a rattling sound in the exhaust system is a bad catalytic converter. The catalytic converter filters the most harmful compounds from your engine's exhaust fumes so they can be safely released into the air. Yet over time, the superheated exhaust fumes passing through the converter may cause it to break down and shed metal pieces. These broken pieces will rattle around the catalytic converter housing and signify it's time to replace the converter before it fails entirely.
Another, more common, cause of rattling in the exhaust system is simply loose parts. Impacts from potholes, years of road vibrations, or corrosion from rust can slowly dislodge parts of the exhaust system such as the heat shield or the hangers and clamps that secure these parts to your undercarriage. The connections on the heat shield, in particular, tend to rust away, allowing it to clank against other metal parts. Loose brackets may also cause your muffler to rattle as your exhaust pipe hits other parts of the car.
Depending on how much the catalytic converter has deteriorated or how loose the other exhaust parts are, you may hear rattling while the car is idling. Before assuming your rattling problem is coming from the converter-the more complicated part to replace-inspect underneath your car for signs of rust and corrosion that may have weakened parts of the exhaust system. If nothing is particularly corroded or moves a lot when pushed, check your catalytic converter and possibly swap it for a new one at your nearest INFINITI service center.
Rattling Noise Around the Wheels
That irritating car rattling sound might also be coming from the wheels. While wheel well rattling probably doesn't mean you're in imminent danger of a wheel falling off, it's safest to solve the problem right away. Here are some potential causes for a rattling noise around the wheels:
Gravel or Debris
A rattling sound coming from a single wheel at low speeds and that disappears at higher speeds could mean that you have gravel or debris rolling around inside your hub cap. Luckily, this is also an easy problem to fix. Simply remove your wheel cover, clear out any debris from the wheel, and put the cover back.
Loose Steering or Suspension
After enough time on the road, various parts of your steering and suspension systems will start to wear out. Shocks and struts may lose their ability to absorb impact, rubber bushings can wear out, and assorted connection points (such as tie rods or the ball joint on a sway bar link) may start to knock around inside their end sockets. In this case, the rattling noise will likely be coming from underneath your car near the wheels, especially while going over rough roads or bumps.
One way to check if your shocks or struts are the source of the rattling is to visually inspect them while another person shakes the car up and down. Touch the coil springs to see if you can feel where the noise is coming from-just watch your fingers!-and check the strut mount as well for excessive looseness. Additionally, if you have the capability to raise your vehicle off the ground, you can shake the wheels side to side and test for any excessive play in the inner or outer tie rods that may cause rattling. Lastly, inspect the sway bar by physically trying to move the bar itself as well as the sway bar links. If the bar moves at all or if there is knocking from moving the sway bar link, that is likely the source of the rattling noise.
Don't wait to get your steering or suspension systems repaired as leaving them unattended can lead to bad wheel bearings and other damaged components.
Poorly-Fitted Brakes
The most common noise associated with brakes is a squealing sound indicating your brake pads are about to wear out. Another normal sound from your brakes is an upward shift in position while stopping in reverse. Yet if you hear rattling coming from your brakes, it may be a sign that a brake pad is not properly fitted, even if it's not worn out yet. Brake pads come with anti-rattle clips to prevent them from becoming loose inside the brake calipers. Without a secure anti-rattle clip, a brake pad is free to knock about inside its caliper.
Rattling Noise Under the Hood
If your car started rattling from under the hood, you could be dealing with a more serious issue. A rattling sound under the hood of your vehicle likely means there is a problem with either an engine accessory or the engine itself.
Engine Accessories
Your vehicle's serpentine belt is driven by the engine and powers important accessories, including the water pump, alternator, and A/C compressor. Over time, however, any one of these components bearings can wear out, potentially causing a rattling noise.
A simple way to check if the problem is related to any engine accessories is to remove the serpentine belt and then briefly run your engine. If the rattling noise disappears, you know the problem lies with one or more of the engine accessories.
Engine Mounts
The engine mounts in your car are used to secure the engine to the frame of the vehicle. If one or more engine mounts is damaged or no longer properly secured, it could be the source of the rattling. If you suspect your engine mounts may be faulty, have your car serviced right away.
Valve lifters are between the camshaft and the engine's valves. They help to open the valves to let fresh air in and exhaust gases out. Noises from these components occur at a faster pace than lower engine noises, and they get faster and slower with engine speed.
Lower engine noises can come from pistons, crankshafts, connecting rods and other related components. These noises are typically slower than upper engine noises and, while they follow engine speeds, these noises may disappear when adding or removing engine load.
Oil is critical for all engine lubrication. Check your engine oil level as a first step for unusual engine noise. Temperature and engine load can also play a role in determining the cause of engine noise. If the oil is topped off, a visit to your nearest service center is likely the next best step for proper diagnosis.
Rattling Noise Inside the Car
If you've narrowed down the rattling sound to inside your car, you can probably breathe a sigh of relief. Rattling within the passenger cabin is commonly attributed to loose items, such as pocket change in a cup holder. In some cases, a loose piece of interior trim may be to blame, such as part of the door's latch assembly or a loose glove box door. Finding the source of this rattling is often as simple as placing your hand firmly against various components and listening for the noise to stop.
Fix the Rattling Noise For Good
Now that you've located the source of your rattling noise, its time to fix it. Order the replacement parts you need from INFINITI Parts & Accessories, and stop by your local service center for help with installation.