Facts Behind the Habit of Shaking the Car While Refuelling

Glancing at the content, the article reports that some motorists shake their car while refuelling to avoid air pockets in the fuel tank. However, the process is designed to fill the tank completely without such actions. Jayan Sentanuhady, a lecturer in Mechanical Engineering at Universitas Gadjah Mada (UGM), stated that rocking the car during refuelling does not influence the amount of fuel entering the tank. Fuel, whether in older or newer vehicles, will fill all of the tank’s space naturally.

He noted that some drivers shake the vehicle with the aim of preventing air entrapment inside the tank. Technically, fuel is a liquid and will flow to fill every space in the tank, including the narrowest or farthest regions. He explained that the density of fuel is higher than that of air; as a result, fuel settles at the bottom of the tank while air is pushed upwards during the filling process. “Air will rise and exit the tank on its own,” he said.

Jayan also pointed out that the habit of rocking the car while refuelling at petrol stations can pose a fire hazard. He explained that when the vehicle is shaken, the nozzle or the end of the fuel hose can rub against the rim of the tank. That rubbing may generate static electricity. According to Jayan, the static electricity from this rubbing can trigger a spark. If a spark occurs in an area filled with fuel vapour, the flame could instantly spread and enter the tank.

Therefore, he urged people not to shake the car while refuelling. In addition to not affecting the amount of fuel taken in, this habit can also raise the risk of a fire at petrol stations.