What Should You Do if You Put Diesel in Your Car?

When you realize that you have accidentally put diesel fuel into your gas tank, immediate action is necessary. Leaving diesel in a gas tank for any length of time is not advisable. Above all, don't start the vehicle under any circumstance. You will want to have your vehicle towed to a garage for drainage right away. Attempting to operate the car could cause the diesel fuel to enter the fuel line and the engine system, which will make the repair process far more complicated and costly.

If the vehicle has a removable drain on the gas tank, this would be the ideal situation. The mechanic will simply open the drain and empty the entire amount of the gasoline/diesel mixture. The tank will then be filled with gasoline and drained again to remove all remaining diesel. This process may require repetition to clear the tank of all diesel contamination.

If there is no removable drain on the gas tank, the tank will have to be removed from the vehicle and drained. This is called "dropping the tank." The mechanic will then rinse the tank repeatedly with fresh gasoline until all the diesel fuel is washed out.

Draining the tank could cost anywhere from $200-$500 depending on whether the tank needs to be dropped and how much diesel is present. If diesel fuel has entered the fuel line or engine, the repair job can easily climb into the $1,500-$2,000 range.