Diesel and Gasoline
Diesel and Gasoline
Diesel fuel and gasoline are both available at most filling stations, but they are very different products. Gasoline is a highly refined crude oil derivative, containing a mix of hydrocarbon chemicals. Most of the chemicals in gasoline contain between five and 15 carbon atoms. Diesel fuel is a less refined, lighter weight crude oil product. In fact, diesel is actually a fuel oil. Most of its hydrocarbons contain 20 or more carbon atoms.
Besides the difference in chemistry, diesel and gasoline behave very differently in the engine. Diesel fuel is meant to self-ignite; there is no spark plug in a diesel engine. The fuel burns due to the pressure and temperature in the engine. Gasoline is blended to avoid self-ignition. Gasoline engines rely on their spark plugs to ignite the fuel.
Because gasoline and diesel are such different fuels, gasoline engines are not intended to run on diesel fuel. Attempting to do so can cause a host of problems.
Most likely, a gasoline engine will simply not run at all in this situation. The diesel fuel is likely to clog the fuel lines, fuel filters and fuel injectors. If the engine does run, it will likely give very poor performance. Because the cylinders in a gas engine do not produce the same temperatures and pressures as those in a diesel engine, the diesel fuel will not ignite properly, and can damage the engines timing cycle and the cylinder linings.
Solving the Problem
If you have accidentally put diesel fuel in gasoline-powered car, stop the car and pull over. If necessary, have the car towed to your home or to a repair shop.
The simplest solution is to simply siphon the diesel fuel out of the gas tank and refill the tank with regular unleaded gasoline. The car should run even if there is some diesel still in the fuel mixture. Expect lower fuel mileage, and more smoke in the exhaust, until the diesel fuel is flushed from the system.
A more intensive fix is to have the fuel system professionally drained and flushed. This will clean the diesel elements out of the system, and allow the car to run properly on a fresh tank of regular gasoline.
Make sure that a good mechanic carefully examines the car. Even if it was only run on the incorrect fuel for a short time, there may be damage to the fuel system or engine. In extreme situations, it may be necessary to replace parts of the fuel system and engine pistons. It’s important to remember that damage due to improper fuel is usually not covered by car insurance, so you’ll have to shop around for the best price on any repair work.