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Rattle Noise Under the Car – Make Sure You Perform Maintenance on Your Exhaust System!

Rattle Noise Under the Car

When trying to figure out what the problem is in your vehicle, it is important to know its onset and where it is coming from. If you hear a rattle noise under the car, this is usually a problem with the suspension or the exhaust system. In order to figure out the root cause of the rattle noise under the car, you need to do some research. 

Auto Repairs Are EXPENSIVE


Thankfully for you, we have researched, so you don’t have to. Keep reading to figure out why the rattle noise under your car might be happening, where it is coming from, and what you can do to solve the issue. 

Exhaust System Function

The car’s exhaust system is the piping used to redirect and guide the reaction exhaust gases away from the combustion source inside the internal combustion engine. The entire system in your vehicle is in charge of turning burnt gases from the engine into usable gases and typically includes multiple exhaust pipes to release the burnt gas. 


Keeping this system in a good working condition is extremely key to the car’s fuel mileage, the environment, your safety, and to prevent the rattle noise under the car.


Most drivers have experienced a curious and concerning noise coming from their car. A rattle noise under the car is no different. It’s always a little nerve-wracking because you think of the worst possible scenario when something is wrong with your vehicle. Some of these noises have simple fixes, while others have more serious and severe concerns. Responding in the right way can help you prevent any problems from worsening over time. 

Causes of the Rattle Noise Under the Car


Unfortunately for you, the rattling noise coming from underneath our car can be due to various reasons, and most often does not boil down to one simple and easy to diagnose the cause. 

  • Turning the Key in the Ignition 

Rattling noises can occur when you first start your car and turn the key in the ignition. The rattle under the car could be due to a faulty ignition switch.

Ignition Switch Function

In modern cars with internal combustion engines, the ignition switch provides the required power to the starter solenoid and the starter system’s other components, like the engine control unit and the ignition coil. The ignition switch works with the other engine components to start the engine at the proper time, ensuring your car does not stall and can function at a high-performance level. 

Faulty Ignition SWitch Signs

Engine Stalling – One of the most obvious signs of a faulty ignition switch is the car stalls while driving. Your engine stalling is a severe issue that needs fixing as soon as possible to prevent any further damage and performance hindrances. There are certain instances where you can determine why your car stalls while driving to prevent the faulty ignition switch.


Key Won’t Turn in the Ignition – The key not turning is a very noticeable symptom of a faulty ignition switch. The first thing you need to do to start your car besides sitting in the driver’s seat turns the ignition lock cylinder key. However, if the faulty ignition switch shows damage inside, it will sometimes prevent the key from moving at all – thereby preventing your car from turning on and your engine from revving,


Car Starts and Stalls – Another symptom that you have a faulty ignition switch is that your car will suddenly start – but then just as suddenly turn off and stall. Suppose the ignition switch is not working while resting in the “on” position. In that case, this can lead to the vehicle starting and stalling erratically. The “on” position is to turn on the fuel ignition systems. Still, if this position is not holding the correct spot, the vehicle will not run.

  1. Try to Accelerate at High Speeds 

The rattle noise under the car can also be most prevalent when you drive the vehicle, and you try to accelerate to high speeds. There are many reasons why your car may not accelerate when you press down on the gas pedal – let’s find out why. 


Three main categories can cause rattle noise under the car and cause your car to have trouble while accelerating. The most common reasons why your car is having trouble is due to:

Actuator Malfunction:

Bad spark plugs, faulty fuel pump, damaged fuel injectors, old fuel wiring, and other fuel component issues

Sensor Malfunction:

A damaged oxygen sensor, faulty mass airflow sensor, broken crankshaft sensor, camshaft position sensor malfunctioning, and sensors in the EFI system

Mechanical Problems:

A dirty and clogged exhaust manifold, broken or dirty air filter, clogged fuel filter, reduced compression 

  • Braking and Stopping Quickly 

Another cause of the rattle noise under the car can occur when you try to press on the brake and stop your car quickly. The sudden and uncontrolled stopping can quickly lead to uneven brake pad wear. Let’s find out some common symptoms of uneven brake pad wear that can cause the car’s rattle noise.

Screeching Noises

First, a screeching sound when applying your brakes might happen. This sound is caused by a small indicator placed in your brake pad for this purpose. If you hear this while braking, it’s time to take your car in for inspection. In addition, if your brakes are constantly exposed to wet or damp conditions, then a layer of dust can form on the brake pads, causing a screeching sound while you brake. 

Grinding While Braking

Second, if it isn't screeching, there might be an audible grinding while braking. If you hear a deep and low noise, this is typically a sign that the brake pads are worn away and that your brake discs and calipers are currently rubbing against each other. This rubbing can be due to the uneven brake pad wear over time. 

Indicator Light

Lastly, your vehicle might have an indicator light that will come on to signal when it is time to replace your brake pads. Be sure to check your vehicle’s manual to see when and how often this usually is, and what the proper indicator looks like. If your light comes on, you’ll have to bring your car to a mechanic to shut off the light, as well as check the brake pads. 

  • Accelerating and Decelerating

You might hear a rattle noise under the car when the car is specifically accelerating or decelerating since this is putting more strain on the transmission and the engine. Also, if you notice that the rattle noise under the car more frequently occurs when your car goes over bumps, rounds a tight corner, or during some tough driving, this can be a clue to the issue’s real cause. 


If your car has problems when you are accelerating, this can be a sign that your automatic transmission is slipping when you press on the gas pedal. So why does this occur and cause the rattle noise under the car? 


Suppose you do not know why the automatic transmission slips when accelerating. In that case, there is usually an answer – and it can sometimes be very severe, requiring you to repair or replace certain parts to fix the issue. The cause of the automatic transmission slipping when accelerating will depend on the kind of transmission that you have in your vehicle. There are three main types of transmission – automatic, standard or manual, and CVT – continuously variable transmission. 

Low Fluid Levels

If you have an automatic transmission and notice that the transmission is slipping while driving, the most common cause of this issue is low transmission fluid. The transmission fluid is necessary to lubricate the parts and keep your car running correctly. 


If your transmission slips, this means that the car engine revs, but no power is transferred to the wheels to move the car. If the sleeping is caused by low transmission fluid, it will get worse as the transmission overheats and friction builds, leading to the rattle noise under the car. 

Burnt Fluid

Sometimes, the automatic transmission slipping when accelerating can be due to the transmission fluid burning instead of just being at a low level in your car. If the fluid is not the right color, like black instead of red, or you notice a burning smell, this is likely the culprit. Burnt fluid can occur when the transmission overheats, and there is too much friction. In this case, you need to swap out your transmission fluid. 

Clutch Problems

Sometimes, the automatic transmission slipping when accelerating can be due to the transmission fluid burning instead of just being at a low level in your car. If the fluid is not the right color, like black instead of red, or you notice a burning smell, this is likely the culprit. Burnt fluid can occur when the transmission overheats, and there is too much friction. In this case, you need to swap out your transmission fluid. 

  • Loose Exhaust System

Your exhaust system is a key part of the running of your vehicle and the fuel system. Your exhaust system spans the length of the engine in your car to the rear of your vehicle. It comprises various components that include the catalytic converter, the muffler, and the exhaust pipe. 

Catalytic Converter Function

The catalytic converter is the exhaust emission control device that reduces the amount of toxic gas and pollutants that occur in the exhaust gas after being produced from the internal combustion engine. 

Muffler Function 

The car’s muffler has the main function of the exhaust system of the vehicle’s engine. The muffler reduces the amount of noise produced by your engine. Also, it is the main part in charge of controlling the engine’s backpressure, improving the longevity of the mechanism and the performance of your car. 


Over time, these components, the muffler, the exhaust pipe, and the catalytic converter, can wear down, causing a rattle noise from under the car. If the joints wear down and become damaged along with the parts, the joints can loosen over time. The loose joints can cause a rattle noise under the car. 


In addition, the exhaust noise might be louder than when you are driving your cars. This rattle noise under the car can appear to come from under the car instead of the rear of the vehicle, showing that the exhaust pipe can be a clear cause of the rattling noise. 


If this is the case and you have noticed and diagnosed that the rattling noise is under your car, this can be solved by having your exhaust system checked by a local mechanic or an auto body shop. You might be surprised that the fix of the rattle noise under the car could be pretty easy and just require the mechanic to check the connections and tighten a loose clamp or replace a damaged hanger. 

  • Faulty Catalytic Converter

Another sign and cause of the rattling noise from under your card could be due to a bad catalytic converter. As we know, this part is a crucial piece to your exhaust system, since it is in charge of the emissions and controls the output of the gases. This piece converts the toxic gases from the exhaust and pollutants into less dangerous substances that can be reused.


The catalytic converter can be damaged over time by extensive wear and thermal shock or a sudden impact, which can result in a piece of the internal structure breaking off – and hence, causing a rattle under your car. In more extreme cases of damage, this can sound very loud and be extremely noticeable while you are driving. 


The solution to the catalytic converter failure is to determine where the original cause of concern is coming from and what caused it to fail, and the rattle noise under the car. Keep in mind that the converter itself can be a very expensive piece, depending on what shop you go to, where you live, and the make, model, and year of your car.


Figuring out the real reason behind the rattle noise under the car can help you figure out what part is causing these issues in your vehicle! Look at your catalytic converter, exhaust system, and other crucial internal mechanisms that can drastically affect the noise and sounds coming from under your car. 

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