What Happens if You Put the Wrong Gas Into a Car?

by Wendy Anderson
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Fueling your car is usually simple. However, if you put fuel with the wrong octane in your gas-powered vehicle, you might see problems, but if you put diesel fuel in your gasoline tank or put gasoline in your diesel, you almost certainly will have an issue.

Wrong Octane

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Putting fuel with the wrong octane in your car is the least problematic mistake to make. Using a higher-octane fuel than the manufacturer recommends will not hurt your car, but using a lower octane fuel can cause engine damage, as well as loss of power and inefficient combustion.

Diesel in a Gasoline Engine

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Putting diesel fuel in a gasoline engine is an unlikely mistake, as the diesel nozzle is too large to fit in a gas tank's opening. Nevertheless, it does occasionally happen. The Automobile Association recommends having the car towed to a mechanic and having the system flushed if you put more than 10 percent of a tank of diesel in your gas tank. If you run the engine with even a small amount of diesel fuel in the tank, you risk damage; the car will smoke profusely and the engine will run very roughly.

Gasoline in a Diesel Engine

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This is the most serious fueling mistake. Burning gas in a diesel engine can damage the fuel injector and the fuel pump. If you put gasoline into your diesel engine, have a mechanic evaluate the damage and flush the fuel system.

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