Hobbies Cars & Motorcycles Does Your Car Need a Fuel Additive Like Dry Gas? Share PINTEREST Email Print Carl Court / Getty Images Cars & Motorcycles Cars How Tos Buying & Selling Basics Reviews Tools & Products Classic Cars Exotic Cars Corvettes Mustangs Tires & Wheels Motorcycles Used Cars SUVs Trucks ATVs & Off Road Public Transportation By Matthew Wright Matthew Wright has been a freelance writer and editor for over 10 years and an automotive repair professional for three decades specializing in European vintage vehicles. our editorial process Matthew Wright Updated April 26, 2018 Your engine is pretty tough, and with fuel management systems as complex as they are these days, your engine's injection system is actually fairly forgiving. Bad gas doesn't always mean a dead engine. But there is one thing that is an enemy of your fuel system on a long and short-term basis - water. Why Water Is a Danger Any level of moisture in your engine is dangerous. Even a small amount of moisture living in a steel fuel tank can cause it to rust. This rust can become catastrophic, resulting in a hole in your fuel tank, a gas leak, and even dangerous results like fire. But even if a rusty tank dodges this type of catastrophic failure, it may still face a slow, painful death that will spread like cancer to all parts of the vehicle's fuel system. Car lovers consider rust to be the automotive version of cancer, and with good reason. It eats away slowly at anything made of iron or steel - car parts. Like cancer, rust can strike in a variety of different ways. One rust attack may weaken a car or truck's frame from the outside, but another may attack it from the inside. This is the kind of rust attack that can happen on the inside of your fuel tank. As water and air cause the inner lining of your steel fuel tank to oxidize, small flakes of metal - rusty metal - are released into the fuel. These little specs of metal are like scouring pads traveling through your fuel injection system and injectors. It will start with the fuel pump. Modern fuel pumps are more sensitive than the older, lower pressure pumps that were on cars years ago. Even a small amount of rust flowing through a new, high-pressure fuel pump on a regular basis can eat it away and eventually cause it to fail. The impeller simply can't take the abrasive abuse. Fuel filters will filter out any large chunks of metal that are moving around in the fuel, but the finest particulate will still make it through to do their damage. Even outside of the rust that water in the fuel tank will cause, there are more immediate effects. If water makes its way out of the tank and into the rest of the fuel system, your car will run poorly or will break down altogether. In extreme cases, water coming through the fuel injectors will accumulate inside your engine's cylinders causing a condition known as hydraulic lockup, or hydro-lock. This can destroy your engine. Water that accumulates in a carburetor can freeze and crack one of the many very delicate parts or passageways in the carb. How to Keep Water Out For these reasons, water needs to be kept out of the fuel system. Modern fuel tanks have a number of ways of doing this. The fact that a modern fuel system is very well sealed is a huge advantage or those of even the late '80s and early '90s. Unfortunately, moisture can begin to build up in your fuel tank by the accumulation of condensation. Many people will use a fuel additive to remove moisture from their gasoline, especially in older vehicles that are more prone to having water in the tank. But are these additives doing any good? Are they necessary? Or worse, could they be harming the components of your fuel system? One of the most popular products on the market is called dry gas. If you examine the active ingredient in this and similar products you will see that alcohol plays the most important role. In fact, it's the only ingredient that does anything at all for the most part. Alcohol bonds with water and keeps it from having an effect on the fuel system. The stuff works, it does the job. Additives like this will keep moisture under control, but modern fuel systems may not be as happy adding this much alcohol its components. Why is this? One reason is the delicate (and cheap) materials used in modern fuel systems. Low-grade rubber and plastics may suffer and degrade when in regular contact with alcohols. But the biggest problem is the fact that the fuel that most people use today is already full of alcohol, as much as 10 percent. It's called Ethanol, it's made from corn, and I'm sure you've already heard of it. If the fuel you use every day contains Ethanol, there's no need for a fuel drying additive. It's redundant and can increase the level of alcohol in your fuel to levels that can cause degradation.