What is a Water Jacket?

Malcolm Tatum
Malcolm Tatum

Water jackets are devices that make use of water to maintain a workable temperature around a piece of machinery. One of the more common examples of a water jacket is the enclosure found around the cylinder block on an engine. By using water to help keep the engine from overheating, the jacket minimizes wear and tear on the engine components, and thus extends the life of the machinery.

Man with a drill
Man with a drill

Many designs for the water jacket are aimed at preventing engines and other types of machinery from overheating. In most instances, the jacket is a chamber that encompasses the motor or other components completely. Typically, the chamber has an inner wall that is closest to the motor, and an outer wall that effectively creates a sealed area around the engine components. This sealed area is constantly flooded with cool water, which in turn helps to keep the engine parts from overheating during operation.

There are also designs for the water jacket that are aimed at heating water. This is true with some designs of the water heater. In this application, the hot water jacket is the chamber that fills with water in a water heater design that is equipped with heating coils. As the coils heat, the temperature of the water inside the jacket also warms. A faucet allows the water to escape from the jacket for use, while additional plumbing allows the jacket to refill with fresh water and continue the process of heating water. Heaters of this type can be used in manufacturing situations as well as a number of other commercial and residential applications.

There are two main benefits associated with the use of a water jacket. First, the jacket helps to minimize wear on motors and other equipment that operate at optimum efficiency when kept below a certain temperature. Maintaining a safe temperature helps to ensure that the components are not overstressed, and makes the process of keeping the motor or engine in good working order.

In situations where the water jacket is essential to the process of heating water, this device makes it much easier to keep the water at a desirable temperature, and to heat fresh water to that correct temperature in a relatively short period of time. The efficient heating process that is created with the use of the jacket means less time and energy spent in keeping water on hand that is ideal for various uses. This in turn can have a positive effect on the overall productivity of a manufacturing plant, a car wash, or any other facility that requires a consistent supply of hot water in order to function.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including wiseGEEK, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


@Vincenzo -- a lot of people do neglect their antifreeze, especially when the weather changes. In cold climates, that can be a problem.

Fortunately, there are inexpensive testers made that allow vehicle owners to pull a sample of the fluid out of a car's radiator and see what temperature that liquid must reach before it freezes. Either changing antifreeze out completely or mixing in some more of the fluid so as to drop the "will freeze" temperature should be something car owners do every fall before temperatures start to drop to the freezing point.


In a car, one should always keep water jackets in mind during freezing temperatures. Why? It is catastrophic for water to freeze in those things and that liquid meant to prolong your engine's life can actually ruin it.

Thankfully, that is the very reason antifreeze exists.

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