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Common Myths About Fuel Pumps

If you have a diesel-fuel vehicle and think it’s safe to fill up at any pump that has a green nozzle, think again. Here are some facts to help you:

  • Diesel fuel and gasoline are dispensed through nozzles that may be green, black, red, yellow or any other color.
  • On some newer pumps, several grades of gasoline are delivered through a single hose and nozzle, which also could be any color.
  • Older fuel pumps may reflect an earlier color scheme, or have had nozzle repairs in which a different colored part was installed.

And, to debunk another belief held by some consumers, fuel nozzle shapes and sizes are also not an accurate indicator of the type fuel being dispensed.

  • Large-diameter filler pipes are usually found at truck stop diesel pumps where they are used to quickly fill high-volume semi-truck fuel tanks. A special adapter is required to use this size nozzle with most diesel passenger cars and light trucks.
  • Medium-diameter filler pipes are used to deliver diesel at passenger-car fuel stations. This size helps prevent fueling errors, because it is too large to fit through the unleaded fuel filler opening.
  • Small-diameter filler pipes are used to deliver unleaded gasoline, but can also fit into the filler opening on many diesel vehicles. Some newer diesel models have a device in the filler neck that prevents a smaller gasoline nozzle from being inserted.

The best advice we can give you: Read the pump label. There are laws that require each type of fuel dispensed be clearly labeled. A few extra seconds when selecting fuel can prevent many hours and hundreds, or even thousands, of dollars in vehicle repairs.