What is the whistle when the engine refuels?

There is a whistle when the engine refuels, which is often called abnormal sound of the refuel door.

There will be a whistle when the engine refuels. Reason:

1, the turbocharger works by exhaust gas, and the engine can't drive the turbine at low speed, so it doesn't work, so there is no sound. Generally speaking, turbines work above 2000 rpm. Going uphill is to resist high speed, empty stepping on the accelerator, etc. And the engine exhaust gas increases, pushing the turbine, so there is sound, which is normal.

2. The engine exhaust valve is not tightly sealed.

3. Diesel exhaust gas recirculation valve (EGR) and gasoline engine throttle valve are not tightly sealed.

4. The exhaust pipe is not tightly sealed or poorly welded.

The above reasons are for reference only, and you need to go to the service station for further inspection and confirmation if necessary.