Why Can I Smell Petrol in My Car?
FixMyCar discusses why you might be able to smell petrol in your car and what you can do to fix it.
Book a car repair nowEllie Dyer-Brown
Tuesday August 05 2025
4 min read
The smell of petrol can be worrying, but there's no need to panic. Some common causes - such as a loose fuel cap - can easily be fixed. Find out why your car might smell like petrol and what you can do about it in this guide.
In a nutshell: Your car might smell like petrol due to a loose or faulty fuel cap, loose spark plugs, an injector leak or another issue with the fuel system.
Why can I smell petrol in my car?
The three most common reasons are fuel leaking from the petrol cap, petrol leaking from the fuel injector or petrol dripping from under the car.
Loose or faulty petrol cap
A loose petrol cap can sometimes cause a petrol smell to enter your car. The cap may even be faulty, which would typically cause the engine management light to appear on the dashboard on newer vehicles.
Make sure the cap is attached correctly and check for any signs of damage.
Loose spark plugs
Loose spark plugs can cause a petrol smell inside the cabin because they allow gas fumes to escape. To see if this is the case, you must first check that all spark plug wires or coils are in good shape.
As you check these wires, note where each goes to avoid putting them back in the wrong place. If in any doubt, have a mechanic do this for you.
If one of your spark plugs is loose, fixing it back in place may solve the problem. However, old spark plugs should be replaced - the recommended interval is approximately every 30,000 to 90,000 miles.
The average quote for a spark plug replacement is £159.17, according to our data.
Petrol smell outside my car
Injector leak
When fuel injectors leak, you will notice a strong smell of petrol towards the front of the vehicle. The first thing to do is open your bonnet and see if you can find the injectors. Look closely for any signs of leaking fuel and increased moisture in the area.
It's unlikely that the main body of the injector is leaking. Instead, the O-ring seal has likely worn out and needs replacing. It's a good idea to clean all fuel injectors at this time.
Fuel injector repairs cost £244.86 on average when booked through FixMyCar.
Petrol smell coming from the exhaust
To identify the cause of a petrol smell coming from the car's rear, run your engine, then smell your exhaust to see if it's the source of the problem. Ordinarily, you should not be able to smell petrol if the engine is running well; if you do, take your vehicle to your local garage as soon as possible.
A strong fuel smell from the exhaust indicates that either too much fuel or too much air is entering the combustion chamber. In addition to a petrol smell, you may also notice black smoke from the exhaust. Below are a few common causes.
Faulty fuel pressure regulator
The fuel pressure regulator controls the amount of fuel that enters the combustion chamber. When it malfunctions, it not only impacts your car's fuel efficiency, but it also causes fumes to sit in the exhaust, creating a strong and unpleasant smell.
Clogged air filters
When air filters become clogged, it restricts air flow, creating an imbalanced air-fuel ratio in the combustion chamber. There is too much fuel, creating sooty deposits, black exhaust smoke, and a petrol smell.
Since there are numerous possible causes of a petrol smell from the exhaust, the best thing to do is book a diagnostic test.
Car smells of petrol when switched off
Sometimes old cars (those made before 1985) give off a slight petrol smell after the engine is switched off. However, this smell should dissipate after a short while. This occurs in older cars such as this beautifully maintained Ford Escort RS2000 MK2 (pictured above), as they are not fitted with the evaporative-emissions system that newer models have.
If you have any concerns about the smell in your vehicle, contact a local garage using FixMyCar.
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Ellie is FixMyCar's Content Manager. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers that is easy understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.