Cummins NT855 Engine Parts for Australia - Engine Water Pump Section

Cummins NT855 Fresh Water Pump & Cooling System Parts Catalog

The Cummins NT855 engine, known for its rugged performance and reliable operation in marine and industrial settings, relies on a well-maintained fresh water cooling system to prevent overheating and ensure long-term engine durability. At Diesel Pro Power, we provide a complete selection of Cummins NT855 fresh water pumps, thermostats, gaskets, hoses, clamps, and cooling-related components — all in stock and ready to ship.

With over 40,000 satisfied customers worldwide, our inventory is trusted for both OEM replacement and marine retrofit applications. Whether you're servicing a Big Cam I, II, III, or IV, we carry the exact freshwater pump and cooling components tailored for your CPL and configuration.

Engine Water Pumps for Cummins NT855

Fresh Water Pump – Big Cam I & II Engines

This Cummins NT855 fresh water pump is designed for early generation Big Cam engines (I and II). Featuring a 4 ½-inch vented impeller and a 4 11/16" multi-groove pulley, this pump ensures continuous coolant flow and optimal cooling performance under high-load industrial and marine conditions.

• Engine Compatibility: NT855 and NH855 Big Cam I & II

• Pulley Style: Multi-groove

• Impeller: 4.5" vented

• Benefits: Designed to reduce cavitation and improve coolant circulation

Fresh Water Pump – Big Cam IV Engines

Tailored for Big Cam IV setups, this NT855 fresh water pump includes a 4 ¼-inch multi-groove pulley and 4.5-inch vented impeller. It is compatible with a wide range of CPLs including:

• CPLs: 9910, 991, 1576, 1502, 1215, 1381, 769, 1383, 1436, 633, 1204, 1145, 1193, 5520, 909, 700, 849, 413, 614

• Application: NT855 Big Cam IV industrial and marine configurations

Built to handle modern cooling demands, this pump is ideal for operators seeking a direct-replacement part with OEM-level performance.

Fresh Water Pump – Small Cam Engines

Designed for earlier Small Cam NT855 and NH855 variants, this pump uses a 5 ¼-inch non-vented impeller and a two-groove pulley. It provides consistent cooling with a non-vented design that reduces air bubbles and potential flow interruptions.

• Impeller: 5.25", non-vented

• Pulley: 2-groove

• Engine Type: Small Cam NT855/NH855

Cummins NT855 Thermostats

180°F Thermostat

A standard 180°F thermostat for general-duty NT855 and NH855 engines. Helps maintain ideal coolant temperatures under moderate operating loads.

• Temperature Rating: 180°F

• Application: General NT855 cooling system use

185°F Thermostat for Big Cam Engines

Optimized for Big Cam engines, this thermostat opens at 185°F, making it suitable for engines running in colder ambient environments or requiring tighter temperature control.

• Compatibility: NT855 Big Cam I–IV

• Use Case: Marine, power generation, or standby applications

173°F Thermostat

A low-temp thermostat that opens at 173°F. Ideal for operations in warmer climates or with engines under constant heavy loads.

• Temperature Rating: 173°F

• Use Case: High-temperature environments, extended duty cycles

Gaskets and Seals for Cummins NT855 Water Pumps

Gasket – Water Inlet Connection

This gasket ensures a tight seal between the pump housing and the water inlet, reducing the risk of coolant leaks and maintaining system pressure.

• Type: Flat-style inlet gasket

• Placement: Water pump inlet flange

Gasket – Water Pump Mounting

Designed for the mounting flange, this gasket maintains a secure connection between the pump and the engine block.

• Ensures vibration isolation

• Prevents coolant seepage during long-term operation

O-Ring Seal – Outlet Connection

This O-ring provides sealing at the outlet side of the pump and is critical for preventing leaks in high-pressure cooling systems.

• Placement: Outlet connection on coolant pump

• Resistant to high temperatures and chemical breakdown

Cummins NT855 Fan Belts

Multi-Groove Fan Belt

An 8-rib serpentine fan belt, measuring 59” long by 1.125” wide, designed for NT855 engines equipped with high-output alternators and water pumps. This belt supports multiple accessory drives, reducing slippage and improving energy transfer.

• Belt Type: Ribbed, multi-groove (serpentine)

• Applications: Engines with multiple belt-driven components

Silicone Coolant Hoses for NT855

To maintain proper coolant flow and temperature, Diesel Pro Power offers a full line of high-temperature silicone coolant hoses in multiple inside diameters. These are rated for marine and industrial environments and offer excellent resistance to pressure, heat, and vibration.

Available Sizes

• ¾" ID – 1 foot

• 1" ID – 1 foot

• 1 ¾" ID – 1 foot

• 1 7/8" ID – 1 foot

• 2" ID – 1 foot

• 2 1/8" ID – 1 foot

• 2 ¼" ID – 1 foot

• 2 ½" ID – 1 foot

• 2 ¾" ID – 1 foot

• 2 3/8" ID – 1 foot

• 3" ID – 1 foot

• 3 ½" ID – 1 foot

• 4" ID – 1 foot

These hoses can be custom-fit to your NT855 cooling system layout and resist degradation from both ethylene glycol and propylene glycol-based coolants.

Hose Clamps for NT855 Cooling System

Ensure secure connections with our marine-grade hose clamps, available in a variety of sizes for both coolant and fuel hoses. Each clamp features high-torque banding and corrosion-resistant finishes.

Clamp Sizing Options

• 9/16" – 1 1/16"

• 1" – 1.5"

• 11/16" – 1 ¼"

• 13/16" – 1 ¾"

• 1 5/16" – 2 ¼"

• 1 9/16" – 2 ½"

• 2 5/16" – 3"

• 2 ⅞" – 3 ½"

These clamps are compatible with all coolant hose diameters listed above and are specifically selected for marine and diesel environments requiring high reliability under pressure.

Temperature Switch for Cummins NT855 Cooling System

Universal Temperature Switch (205°F)

This temperature switch fits Cummins, Detroit Diesel, and Caterpillar engines and is commonly used to control cooling fans or warning alarms.

• Closing Temp: 205°F

• Thread Size: ½” NPT

• Application: Fan or warning circuit control

Radiator Cleaner – Marine and Industrial Use

For deep-cleaning the NT855 radiator and cooling circuit, our radiator cleaner is formulated to break down scale, rust, and sediment without damaging metal components. Available for ground shipping in the U.S. and Canada.

• Safe for aluminum and copper/brass radiators

• Compatible with Cummins coolant formulations

Mechanical & Electrical Gauges

Maintain visibility into your engine’s temperature, pressure, and voltage with our selection of:

• Mechanical gauges with and without alarms

• Electrical gauges in 12V and 24V variants

These gauges are essential for proactive monitoring of your NT855’s coolant system and preventing thermal overload.

Why Proper Freshwater Cooling Matters for the Cummins NT855

The NT855 is a heavy-duty workhorse engine, often deployed in marine propulsion, auxiliary power, and industrial operations. It generates substantial heat during operation, making freshwater cooling essential for:

• Preventing thermal expansion damage

• Maintaining combustion efficiency

• Extending engine oil life

• Avoiding piston scoring or cylinder head warping

A worn-out water pump, leaking gasket, or collapsed hose can quickly escalate to serious engine failure. That's why all components in this catalog are selected for their OEM-grade durability, precise fit, and long service life.

When Should You Replace a Fresh Water Pump?

Signs your NT855 water pump or cooling components may need replacement:

• Engine running hotter than usual

• Coolant leaking from the pump housing

• Noisy or seized pulley bearings

• Steam from exhaust or coolant overflow

• Reduced coolant circulation

• Thermostat not opening at correct temperature

If you’re experiencing any of these symptoms, we recommend replacing the pump and related gaskets, hoses, and clamps as a system to prevent repeat failures.

Trust Diesel Pro Power for Your NT855 Cooling System Needs

All components listed in this catalog are in stock and ready to ship. We carry only high-quality replacement parts specifically engineered for the NT855 and NH855 platform, including Small Cam and Big Cam variants. With fast worldwide delivery, easy online ordering, and knowledgeable customer support, Diesel Pro Power is your one-stop source for Cummins engine cooling system parts.

Need help choosing the right pump or hose size for your CPL? Contact us and we’ll make sure you get the correct part for your configuration.