Why Is My Car Making a Rattling Noise?
- Diagnostic
FixMyCar discusses why your car might be making a rattling noise.
Book a car repair nowEllie Dyer-Brown
Tuesday September 24 2024
5 min read
Nobody wants to end up with an expensive repair bill, but getting problems fixed as soon as they happen can save you lots of time, money and stress in the long run. That’s why it’s essential not to ignore rattling noises (even if you really want to).
This guide takes you through the most common causes of rattling so you can decide whether to tackle the problem yourself or leave it to a mechanic.
In a nutshell: Your car could be rattling due to a loose exhaust system, faulty suspension, low engine oil, loose objects in the cabin, a cracked serpentine belt or a broken catalytic converter.
What does it mean if my car makes a rattling noise?
If your car is making an unusual rattling noise, there could be several causes. In most cases, it will have something to do with a loose part or component. The easiest way to determine what is causing the noise is to pinpoint which area of the car it's coming from.
Rattling noise under my car
1. Loose exhaust system
If you hear rattling from under the back end of your car, it’s a sign that the exhaust system has become misaligned. Alternatively, the silencer, positioned right by the exhaust pipe, could have come loose. Both problems can easily be fixed and shouldn’t cost too much money.
How much does it cost to fix a loose exhaust system?
The average price of an exhaust repair booked through FixMyCar is £121.36.
2. Faulty suspension
If you hear rattling while going over potholes or speed bumps, your suspension is likely at fault. Issues could come from one of the many components of the suspension system, including control arms, ball joints, tie rods, strut mounts or the sway bar link.
Unless you have decent mechanical knowledge, the best course of action is to take your car to a garage to have the suspension system checked by a professional.
How much does it cost to fix a car's suspension?
Suspension repairs cost £135.27 on average when booked through FixMyCar.
Rattling noise under my car bonnet
1. Low engine oil
The first thing to check if you can hear a rattling noise under your car’s bonnet is the engine oil level. When there isn’t enough oil circulating through your engine, it can cause rattling as different parts rub together without lubrication. Top up your oil as needed to avoid causing severe damage, and don't forget to check for a leak that may have caused the low fluid level.
How much does an oil change cost?
The average price of an oil change is £116.30, according to our data.
2. Cracked or broken serpentine belt
The serpentine belt (also known as the fan belt) drives your car’s alternator, AC compressor and water pump. If you’re not sure how to tell the difference between a serpentine belt and a timing belt, the latter can’t usually be seen because it’s hidden under protective covers.
Driving your car with a faulty or broken serpentine belt can cause the engine to overheat, so the best thing you can do is open up the bonnet to have a look and decide whether you can take the car to a mechanic yourself or if it will need towing.
How much does it cost to fix a serpentine belt?
On average, a serpentine belt replacement costs £123.28 when you book through FixMyCar.
Rattling noise when accelerating
1. Broken catalytic converter
Your catalytic converter consists of small, honeycomb-shaped pieces that can cause a rattling noise when broken. If this is the case, the rattling will be loudest when you start the engine and worsen over time. Unfortunately, catalytic converters are often expensive to replace, but this isn’t a job you can put off.
Learn more about what a catalytic converter is and how it works.
How much does it cost to fix a broken catalytic converter?
The average price of a catalytic converter replacement is £433.80.
2. Rattling noise inside car
The good news is that any interior rattling is likely down to something small and can probably be fixed by you. Check the interior for any objects that are loose and could be causing the rattling. The glove box is an excellent place to start. You should also check the in-door storage pockets.
If you can’t find an obvious noise source, you might need to take your car to a garage where they can look for any underlying causes.
If you have any other issues with your car that you'd like to try and diagnose yourself, check out our guide on self diagnosing car problems. The more you know about how your car works, the better.
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