The smell of petrol within the cabin of the car can be a cause for concern as fuel is a highly flammable substance. While it’s expected for the smell to linger outside a bit when refuelling, it can be a worrying sign when the smell is prominent when driving or idling. In this article, we cover the most common causes of petrol smell and what to do.
Why can I smell petrol inside my car?
Loose or damaged fuel cap
It is possible for gas vapour to escape from a missing, loose, or damaged gas cap when you start the car. It could just be the case that you missed closing it properly after refuelling. If the cap is secured and you still smell fuel then it could be damaged or cracked somewhere else. Getting a replacement cap is inexpensive and fairly straightforward with options available online.
Faulty fuel pressure regulator
A fuel pressure regulator regulates the pressure of fuel that is delivered to the engine. If it is faulty then the excess fuel not only wastes petrol or diesel, but also causes fumes to sit inside the exhaust, which could result in the petrol smell you notice in the car (or even outside). When you notice a decrease in fuel efficiency, a bad fuel pressure regulator may cause the car’s petrol smell. Fuel smell from the exhaust can also be caused by a broken ignition coil so it’s best to consult a mechanic to find the source of the problem as soon as possible.
Loose spark plugs
Loose spark plugs can cause a petrol smell inside the cabin by allowing the fumes to escape. To determine if this is the case, you must first inspect all spark plug wires and coils, as well as the torque on the spark plugs.
Leak in fuel system
Another reason why you may smell petrol when you start up the engine is that there may be a leak somewhere in the fuel system. It could be due to a leak in the fuel line or a puncture somewhere within the fuel system components. It’s absolutely critical that you do not drive a vehicle in this condition before getting it inspected by a mechanic.
There can be a pungent fuel smell when an exhaust leak occurs since there are a lot of unburned gases in the exhaust before the catalytic converter filters them out.
Oil cap’s O-ring or gasket
If there is a fuel smell coming from the oil cap, it is likely that the o-ring is not sealing properly. Open the hood and examine the area surrounding the oil cap to determine if there is oil or debris collecting on the valve cover. If so, the o-ring is likely worn out or gone hard and is leaking fumes from the engine. This smells like fuel and is being drawn into the fresh air intake located directly below the windshield, known as the HVAC (Heating Ventilation Air Conditioning). This is easy and inexpensive to replace.
Petrol smell outside the car
A leak with the fuel injectors may cause a small from the front of the car whereas if you can smell it from the rear end then it’s likely coming from the exhaust (which could indicate the engine isn’t running as it should). A lingering fuel smell in or outside the car should not be ignored and you should get it inspected and fixed as soon as possible.