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  • VIDEO: What Happens When You Put Gas in a Diesel Engine?

VIDEO: What Happens When You Put Gas in a Diesel Engine?

U.K. TV Show Runs the Experiment

Dec 28, 2015
Gas or diesel is a question you should only ask yourself when buying a new vehicle, not when refueling it...
In the United Kingdom, where diesel engines abound, “misfueling” is an apparently common occurrence when a careless motorist puts gasoline in a diesel engine or diesel fuel in a gasser. But what are the ill effects of such a blunder? Jon Bentley, a presenter from the U.K. TV show Fifth Gear, set out to find out in a Throwback Thursday video posted to the show’s YouTube channel.
First, let’s get the caveats out of the way: Bentley is using two older gasoline and diesel vehicles. The Ford Escort gasser is a European-market sixth-generation model, which debuted in 1995, and the Vauxhall Astra diesel is even older, dating to 1991. Modern cars use higher-pressure fuel pumps and more sophisticated emissions control systems, so the effects could be worse than on these old lumps. Additionally, Bentley’s methods are a bit less than scientific, so don’t go writing your master’s thesis using the video as your primary source.
Both cars run fine on the wrong fuel initially, presumably as the last fumes of the correct fuel make their way through each respective fuel system. But after a few miles, the Escort filled with diesel begins to hiccup and cut out randomly, resulting in the kind of head-tossing shudder that would fill any driver with dread. And although the Astra ran for a longer distance on gasoline, eventually it cut out completely and refused to run. The solution? Bentley just refills the tank with the correct fuel, and after a few moments of hesitation, each vehicle runs as it did before.
But Bentley acknowledges that those modern diesel fuel systems, what with their higher operating pressures and finer tuning, could be easily damaged by running non-lubricating gasoline through a diesel fuel pump, and a new gasoline engine’s emissions could be easily damaged by diesel’s less refined oil content. So don’t get careless at the pump unless you’re driving a European econo-sedan from the 1990s.
Source: Fifth Gear via YouTube