What Causes the Smell of Gasoline When the Car is Cold?

[StLila]

The reasons for the smell of gasoline when the car is cold are: 1. Insufficient air intake in the throttle; 2. Problems with the carbon canister or carbon canister solenoid valve; 3. Excessive carbon deposits inside the engine, leading to poor atomization of the air-fuel mixture; 4. Leakage in the fuel injector; 5. Low external temperature, causing the mixture to not burn completely and be directly discharged through the exhaust pipe; 6. The solenoid valve remains closed; 7. Aging of the carbon canister rubber hose. Precautions for cold-starting the vehicle: 1. Since the components of the starter are not fully lubricated and the engine's operating temperature has not reached the optimal working temperature, avoid prolonged idling to warm up the engine; 2. The fuel injector automatically increases the fuel injection to raise the RPM, and the vehicle can be driven normally once the engine temperature reaches the optimal working temperature.

[McGage]

I'm quite familiar with the smell of gasoline when the car is cold, having encountered it occasionally over the years of driving older vehicles. The most common cause is a fuel system leak, such as aging or cracked fuel tanks or fuel filler pipes, where gasoline drips out when parked, especially in cold weather when plastics become brittle and more prone to cracks. Another issue could be with the charcoal canister, which is responsible for collecting fuel vapors. If it's clogged or damaged, vapors can escape during a cold start, just like with my old car—once it was fixed, the smell disappeared. Additionally, a faulty oxygen sensor might cause the air-fuel mixture to be too rich, leading to incomplete combustion upon startup and producing a gasoline odor. I must remind you, if you smell gasoline, stop immediately and check under the hood for any signs of leakage. Don’t delay, as there's a risk of fire. During regular maintenance, ask your technician to specifically inspect these components. It can save you a lot of trouble and also improve fuel efficiency.

[MacBrandon]

As someone who often helps friends inspect their cars, a strong gasoline smell when the car is cold usually stems from issues with the evaporation system. When the charcoal canister is clogged or the valve is damaged, gasoline vapors cannot be recycled, resulting in a strong odor before starting the engine. It could also be due to aging or cracked fuel lines, or a loose seal on the fuel filter causing leaks. I once encountered a car where the fuel tank cap had a poor seal, allowing vapors to escape through the cap hole. I recommend first checking for oil stains under the car. If there are no leaks, it's likely an issue with the charcoal canister or related fuel lines. The repair isn’t difficult—usually just cleaning or replacing the parts, with reasonable labor costs. However, don’t overlook safety; prolonged exposure to strong gasoline fumes is harmful to health. If you smell it, open the windows for ventilation and drive slowly to a repair shop. Make it a habit to walk around the car before ignition to spot potential issues early.

[MacVivian]

When I was a new driver, I also had this question. Now I understand the common reasons for gasoline smell when the engine is cold. First, it could be a fuel tank leak caused by cracked plastic parts due to freezing or corrosion holes. Second, the sealing rings near the fuel filler pipe or fuel injectors may have aged, allowing gasoline to seep out. Third, the charcoal canister might be saturated and clogged, causing fuel vapors to escape. Fourth, a faulty oxygen sensor can lead to excessive fuel supply without proper combustion. If you notice the smell, don’t panic. First, check for any signs of fuel leakage or unusual noises, then try starting the engine to see if the smell diminishes. If the odor persists, don’t attempt DIY fixes—take it to a professional shop for inspection. Safety first. New drivers should learn to perform regular maintenance, such as checking the evaporative system every six months, to prevent such issues and extend the vehicle’s lifespan.