What to Do If the Wrong Fuel is Added at the Gas Station?

[PatrickFitz]

There are three scenarios when the wrong fuel is added at the gas station: the fuel tank is empty; there is residual fuel in the tank, but the wrong octane rating was added; or gasoline and diesel were mixed up. Below are detailed explanations for each scenario: 1. Empty fuel tank: (1) Higher octane fuel added: Higher octane gasoline reduces knocking, making the engine quieter. However, due to the engine's lower compression ratio, prolonged use may lead to incomplete compression and combustion of gasoline, resulting in sluggish acceleration while driving. (2) Lower octane fuel added: While driving, non-evaporative residues from lower-octane gasoline can deposit in the fuel tank, fuel lines, and fuel filter, clogging the lines and injectors, which may interrupt fuel supply and cause the vehicle to stall. This can also increase cylinder temperature, cause incomplete combustion, and reduce power output. Knocking typically occurs during rapid acceleration or uphill driving. If the engine experiences prolonged knocking, it may damage the engine, even breaking the piston or cylinder block. 2. Residual fuel in the tank, but the wrong octane rating added: This situation is equivalent to mixing different octane fuels. Short-term mixing of different octane gasoline will not cause significant harm to the car, but long-term mixing may affect the lifespan of the ignition system, fuel injectors, and spark plugs, advancing the need for major repairs. The impact varies depending on whether a higher or lower octane fuel is mixed. For example, a car designed for 92-octane gasoline may not face significant issues if 95-octane is added, but the reverse could lead to vehicle damage. Using lower-octane gasoline may cause knocking, and in severe cases, could bend valves or damage the valve cover. In such cases, it is advisable to drive the car to a repair shop to drain the fuel tank and refill it correctly. 3. Gasoline and diesel mixed up: Diesel engines operate on compression ignition, while gasoline engines rely on spark ignition. If gasoline is added to a diesel car, the vehicle may shake, emit black smoke from the exhaust, or fail to start. If diesel is added to a gasoline car, the engine may start but will lose power after driving a short distance, with unstable idling.