Pouring a sack of sugar into someone’s gas tank is almost a revenge cliche. We have all heard stories of friends of friends doing it and seen it in fiction.
However, most of us have probably never seen its effects in real life and many people have doubts that sugar can, in fact, damage an engine so thoroughly. The reality is that sugar is both granular and melts at a temperature that engines can easily reac,h so it has multiple avenues to damage an engine.
Granular Sugar Physically Clogs Engines
Two major properties of the relationship between sugar and gasoline, that make putting sugar in a gas tank so destructive to an engine.
- Sugar is only a little over twice as dense as gasoline, which means that once sugar is poured into a gas tank and the engine begins moving, vibrations created by the engine keep the sugar suspended in the gasoline.
- This problem is exacerbated by the fact that sugars are polar molecules, meaning that electrons congregate to one side of the molecule and that the hydrocarbons in gasoline are nonpolar. Nonpolar liquids do not dissolve polar solids well and vice versa, meaning that the sugar remains solid in gasoline indefinitely and that it is impossible to try to flood the sugar out with more gasoline or waiting for it to dissolve. The sugar will never dissolve.
The suspended grains of sugar wreak havoc by clogging up the fuel filters and even the fuel pump. If the engine gets hot enough before clogging, the sugar may melt and seep into the engine’s mechanisms, gumming them up and damaging them irreparably. Eventually, the buildup of sugar granules on the filter and fuel pump will completely block it up and render the engine unusable. In the meantime, problems like stalling, poor fuel efficiency, and low power will become increasingly prevalent.
Sugar Chemistry Makes it Destructive to Engines
Table sugar, or sucrose, is a dimer—a large molecule composed of two smaller molecules called monomers that have been bonded together. Sucrose dimers have a monomer each of glucose and fructose molecules. The backbones of both glucose and fructose are composed of one oxygen atom and a chain of either five or four carbon atoms for glucose and fructose respectively. Depending on the conditions of the molecule, the chain may connect at one point on the oxygen, forming a linear atom, or at two points, forming a ring.
When both glucose and fructose are in the ring configuration, they easily bond to each other to create sucrose. The opposite is also true. Sucrose easily breaks down into glucose and sucrose, especially at high temperatures. Once the sucrose is broken down by an engine’s heat into its component monomers of glucose and fructose, the temperature will also make the linear configuration predominant. Ultimately, the high heat causes the sugar monomers to be broken down into smaller parts, creating a complex and messy chemical sludge that can destroy most of the delicate components in an engine like fuel injectors.
While sugar in a gas tank sounds like an amusing idea, the truth is that sugar destroys engines through both physical and chemical means. Beyond being expensive, this kind of vandalism is dangerous and a felony criminal offense. Doing so exposes the car’s operator to significant danger and causes thousands of dollars of property damage at the least.