This is what can happen if water gets into your gas tank – Jalopnik

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The car industry is awash with all kinds of alternative fuels for internal combustion engines, from LPG to ethanol, cooking oil to hydrogen – there is even a biofuel made from invasive seaweed. But despite widespread urban myths to the contrary, there’s one thing an engine can’t run on: water. If water gets into your gas tank, it can cause your engine to run very poorly or not at all, and even damage and corrode your fuel system, including the fuel pump and injectors.

Water, one of the most common contaminants in motor oil, also has a nasty habit of entering gas and diesel systems, either through condensation, when moist air cools and forms water droplets, or through infiltration, when water seeps into the fuel. This can happen in several ways, such as a defective or missing fuel cap, a leaking seal in your fuel system, refueling in high humidity or rain, or refueling from a contaminated stock.

Most gas stations store their fuel in underground tanks, and although these supplies are carefully filtered (or at least they should be) and checked for quality, water can still seep in. If you are unlucky enough to fill a tank with this contaminated gas, your car will let you know within minutes of driving away by sputtering, stuttering, stuttering or cutting out completely. You may even get the dreaded engine warning light.

While water in your gasoline will make your car run like a hairy goat, it won’t cause catastrophic engine failure. But it can cause corrosion and damage over time, so it’s best to identify the problem and do something about it as soon as possible. In addition to the general symptoms of poor starting, rough idling, stalling and hesitation when accelerating, another indication is that the fuel smells. Although if you don’t have a habit of sniffing gas, this may not be a foolproof diagnosis.

Fortunately, a more accurate DIY method is available in the form of water detecting pastes, like this one from Amazon. You apply the paste to the end of a stick, dip the stick into the fuel tank and if it changes color – usually bright red, blue, green or pink – then you indeed have water in your fuel. Make sure your stick reaches the bottom of the tank. Water does not mix easily with gasoline or diesel and will instead settle to the bottom, leaving the fuel floating on top.

Once you have a positive diagnosis, you will need to drain and clean your fuel tank. This is not without risks – not only of explosions, but also of further contamination. If your DIY skills aren’t up to par, call in a professional who can perform a complete fuel system flush. If you think your gas station sold you bad gas, it may be worth taking these additional steps to claim compensation.