What Happens if You Put Sugar in a Gas Tank?

FAQ

You’ve probably heard the stories of how it’s the absolute worst thing you can do to a person to pour some sugar into their gas tank. As a general, oft-unspoken rule, this is a heinous act that only awful people do to other, usually equally awful people, for vengeful purposes. It’s become an urban legend, and we’ve probably seen it in enough movies. The big question, though, is whether it’s true or not.

The story goes that if you put sugar in someone’s gas tank, the car will immediately be disabled. The sugar is supposed to take part in some kind of reaction with the gasoline and turn into a gooey, semi-solid substance that clogs up everything from your gas tank to your fuel lines and beyond.

Is that true? Does the sugar turn into the goo from hell? Other stories claim that the sugar will caramelize and fill your gas cylinders with some carbon deposits that will just ruin everything.

Well, it’s a rumor, but it’s not true, folks. We went and tested it and, as it turns out, isn’t a true one. Now, bear in mind that sugar finding its way into your fuel lines or your cylinders certainly is a bad thing. But, on that note, any other kind of particulate substance, such as sand or salt, will cause the same damage. It’s about the particulate nature of sugar, not its chemical nature.

Does Sugar Dissolve in Gasoline?

To start with, sugar does not dissolve in gas. That means it’s going to have a difficult time circulating through the engine of your car. There are experiments that have actually been performed to determine this. John Thornton, a professor of forensics at the University of California, Berkeley, tried to mix sugar that had radioactive carbon in it with gasoline. He then spun out the sugar through the gasoline using a centrifuge and measured the radioactivity of the gasoline as a way to find out just how much of the sugar might have dissolved in it.

The result was minuscule. Only about a teaspoon of sugar dissolved in 15 gallons of gasoline. This isn’t enough to cause an issue in a car with an average gas tank. With a car whose gas tank isn’t full, an even smaller amount than a teaspoon of sugar will dissolve because there will be much less solvent. Perhaps the worst thing you will have to worry about is how much less gas you’ll be able to put into your tank if it’s sugared. After all, sugar is much heavier than gasoline.

You might also experience a problem if the sugar gets a chance to be suspended in the gasoline in your tank, such as when you hit a bump or a pothole in the road. It will find its way to the fuel filter, and a small amount of it will be caught there. But that’s what a fuel filter is for: catching particulate matter and stopping it from finding its way into the fuel lines. You’ll probably have to change your fuel filter a lot more often until the problem is solved, but not much more than that.

Now, if a large amount of sugar was poured into your gas tank, such as a whole bag of sugar, you would have a bigger problem. You wouldn’t be able to put in much fuel into your gas tank, and you would probably have to change your fuel filter too many times to make any financial sense. The best option would be to have your entire gas tank removed and cleaned out by a professional mechanic. This will set you back between $100 and $200. That sounds like a lot of money, but it’s way better than having to replace the whole engine!

Water is a much more effective Engine Killer

If you really want to do in someone’s engine, water will do a better job. Water will completely mess up the combustion process that makes an engine run. As it turns out, water is much heavier than gasoline, and so will sink to the bottom while the gasoline floats on top. That means the fuel lines will carry either water or a mixture of water and gasoline to the engine. Your engine won’t die, fortunately, but you’ll need to give it a fuel treatment for a few hours.