Does filling up the gas tank in summer affect the car?

[MakaylaDella]

Filling up the gas tank in summer does affect the car. Here are the specific details: 1. Driving safety: The car's fuel tank has a vent hole at the top. If the tank is filled to the brim, gasoline can easily overflow from the vent hole. 2. Tank deformation: The fuel tank has a fixed capacity, and leaving some space prevents gasoline expansion. If the tank is overfilled, gasoline will expand due to heat from the sun, which can deform the tank. 3. Vehicle performance: More gasoline increases the vehicle's weight, requiring the engine to consume more fuel to move the car. 4. Other effects: It can severely reduce the performance of the carbon canister, leading to engine shaking, increased fuel consumption, faster gasoline evaporation, and gasoline odors entering the cabin, which can harm health with long-term exposure.

[McBryce]

Having driven for over a decade, I really don’t recommend filling up the gas tank completely in summer. High temperatures cause gasoline to expand, and if the fuel level exceeds the safety line, overflow is no joke—especially when parked under the sun, the smell of leaked fuel under the car is awful. Worse yet, the charcoal canister can easily get clogged, and repairing it costs several hundred bucks. Normally, filling up until the pump clicks off is enough—it saves fuel and is safer, leaving some space in the tank for gasoline’s thermal expansion. If you’re going on a long trip, refueling midway is better than taking risks. Experienced drivers all know this principle.

[LaLillian]

Last summer, I filled up the tank for convenience, but then there was always a gasoline smell in the car. Later, I asked a friend and realized it was a serious issue. High temperatures cause gasoline to expand, and if the tank is too full, it can overflow through the vent pipe, not only wasting money but also potentially damaging the fuel tank cap seal. Additionally, the increased weight of the car can raise fuel consumption by half a point, making it uneconomical for short commutes. Now, I only fill up to three-quarters of the tank, which is just enough for a week. By the way, when the carbon canister got clogged, the engine warning light even came on, and the repair cost was enough for several tanks of fuel.

[EleanorAnn]

Gasoline volatility is stronger in summer, and a full tank leaves insufficient space, making it easy for fuel vapor to enter the charcoal canister. Over time, the charcoal canister becomes saturated and needs replacement, costing at least three to four hundred yuan for parts and labor. For optimal safety, I usually fill up to the automatic shut-off and then add two more liters. This ensures the fuel pump is fully immersed in gasoline for cooling without overloading the vapor system. As for the impact of weight on fuel consumption, actual tests show a full tank consumes 2% more fuel than a half tank, which is unnecessary for short commutes. However, it's advisable to fill up for occasional highway trips to avoid frequent stops at service areas.