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Expansion Tanks

Expansion tanks are typically fitted to collect coolant as the engine or hot water system heats up. They enable the system to contract and expand when cooling off and warming up, providing head pressure for the circulation pump. Expansion tanks also make inspections and maintenance tasks easier. Learn more about the expansion tanks Orca Marine Cooling offers and the industries we serve.

Expansion Tank Features

At Orca Marine Cooling, our expansion tanks are made with copper and fitted with a pressure cap with at least one hose connection. You can purchase expansion tanks in both vertical and horizontal styles to accommodate your engine’s needs. There are mounting brackets available that will allow for various mounting configurations, while stainless steel clamps hold the reservoir in place. If needed, we can connect an overflow recovery bottle to the provided fill neck tubing fitting.

Orca Marine Cooling Systems also offers replacement expansion tanks for original models by engine manufacturers. We provide horizontal reservoirs with different threaded or hose fittings. Our team can work with you to create a customized expansion tank to fit unique requirements. 

Industries Served

Various marine applications and industries use expansion tanks. Orca Marine Cooling is a top provider of coolant expansion tanks for the following industries. 


Boat transportation includes three main types of marine engines: diesel, gas turbine, and natural gas. Regardless of the engine type, each one works by using a turbine to convert the fuel to mechanical energy, creating propulsion for the ship. Oil tankers, bulk carriers, container ships, and general cargo ships are a few ships that use these types of marine engines. All marine engines require a coolant expansion tank to reduce excess pressure. 


Many modern Navy ships use reciprocating diesel engines because of their simplicity, robustness, and fuel economy compared to other engine types. 

Travel & Leisure

Cruise ships typically use multiple common rail engines to power the vessel. Each engine produces around 19,480 kW of water, so expansion tanks are necessary to maintain optimal engine pressure. 

Commercial Fishing

Marine engines for commercial fishing ships are about more than just propulsion. They are also designed for efficiency and to reduce the environmental footprint of the boat’s engine. While there are other emerging marine engine technologies, the common engines used in commercial fishing vessels include: 

  • Diesel: The industry standard marine engine capable of producing both low and high engine speeds. 
  • Diesel-Electric: Marine engines use a diesel engine to produce electric power throughout the ship. The engine can be placed independently of the propeller location, which helps reduce noise and vibration.
  • Gas Turbine: Gas turbine engines use the Brayton cycle to create internal combustion and generate power, resulting in extra speed for the vessel. They are not as efficient at low speeds, so they are usually used with diesel engines.

Expansion Tanks by Orca Marine Cooling Systems

Expansion tanks are essential to marine engine cooling systems to ensure the boat’s engine operates efficiently in its demanding environment. Systems without an expansion tank can undergo extreme stress, leading to premature engine failure. 

For more than five decades, Orca Marine Cooling Systems has been manufacturing heat exchangers, cooling systems, and expansion tanks for various marine applications. We can match heat exchangers and system kits to the exact requirements of a particular engine. If needed, our team can also custom-design our expansion tanks and cooling systems to fit unique needs. 
Contact us to learn more about our expansion coolant tanks and how we can assist with your marine system needs. 

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