Engine Coolant Temperature Switch Cat – In-depth Guide


The cooling system is a vital part of the engine health management for vessels of all sizes and types. Besides boosting fuel efficiency, powerful cooling mechanisms contribute to extended engine lifespan. Modern cooling units are integrated into the digital engine control unit (ECU) for effortless equipment health monitoring through real-time data analysis. The mechanism is based on a complex mechatronic framework comprising sensors and monitoring systems. The engine coolant temperature switch is one such sensor connected to the cooling system.

In this blog post, we are offering a comprehensive guide to coolant temperature sensors in ship engines. Read on to learn what it is, the best items for marine applications, and more.

What is an Engine Coolant Temperature Switch (ECT)?

A coolant temperature switch is a temperature-sensitive device used to measure the pressure and temperature of the coolant in the engine. This is a prominent protective resistor (with a negative thermal coefficient) located in the engine block.

An ECT is connected to a dual-wired thermistor and partially submerged in the coolant to monitor the temperature of the fluid. This system is connected to the computerised engine control unit (ECU) through a circuit. The sensor sends a voltage variable signal to the computer monitoring system in the cockpit. Such real-time alerts at low oil pressure levels help vessel operators detect overheating problems quickly. This entire process warns the operator to shut down the engine temporarily for cooling to prevent massive failure or damage.

However, the low oil pressure level is never the same for all marine engines. The manufacturers set the recommended levels based on the engine type, configuration, and other factors.

How ECT Work in Marine Engines

The temperature sensor immersed in the coolant remains in open or closed state. When the temperature of the coolant rises, the engine coolant temperature switch closes to earth and vice versa. At the point of closing, the sensor sends a warning to stop the engine to prevent further heating.

The opening and closing position of the sensor produces resistance variation. It is not possible to decipher this variation by the ECU. Therefore, the device is connected to an electrical circuit with +5V reference voltage to convert the resistance variation to voltage variation. The ECU generates coolant temperature data based on the variable voltage produced by the coolant temperature sensor. Additionally, the entire system must have a highly functional multi-meter reader to send alerts to the computer onboard.

Why Choose Cat Coolant Temperature Switches

There is no looking beyond the Cat Water Temperature Switch for Caterpillar engines onboard. These electromechanical devices offer supreme endurance to shocks, vibrations, moisture contact, and debris. Cat switches feature the exact configuration to match the brand’s engines and cooling equipment to deliver best-in-class performance. The high-quality material and design offer supreme accurate functioning in extreme temperature ranges and resistance to wearing and corrosion.

Part number 2358747 is compatible with various Cat machinery, including industrial engines, wheel-type loaders, backhoe loaders, C4.4DE55E2 engine generator sets, and more.

Visit our product gallery or reach out with the required part number to purchase top-quality OEM replacement parts for your vessel.

Are you looking for genuine Cat coolant temperature sensors?

Alfa Marine Spare Parts is one of the leading suppliers of Caterpillar spare parts. From fully assembled marine engines to minute parts, we sell over 80,000 products from Cat, Cummins, Wartsila, Volvo Penta, Perkins, Scania, and many other brands.

Browse our web catalogue to view our entire range of marine cooling solutions. We ship marine spare parts globally.

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