Cummins 4BT Marine Water Pump and Cooling System Parts Catalog

If you're running a Cummins 4BT in a marine application, efficient cooling is vital to preserving engine life and ensuring reliable vessel performance. This catalog showcases Diesel Pro Power's complete selection of marine raw water pumps and compatible cooling system components tailored for the Cummins 4BT engine. With over 40,000 satisfied customers worldwide, we deliver durable, saltwater-rated solutions that withstand the harshest conditions.

Complete Marine Raw Water Pump for Cummins 4BT

Raw Water Pump with Gear

• Engine Compatibility: 4BT3.9, 4B3.9, 6B5.9 marine variants

• Inlet/Outlet Port Type: 1 1/4” hose

• Configuration: Gear-driven

• Application: Directly draws seawater from the intake system to feed into the engine's heat exchanger or oil cooler

This pump is specifically designed for the Cummins B Series marine platform. Its bronze marine housing and integrated gear system make it suitable for continuous-duty marine environments, preventing overheating and supporting stable operating temperatures under load.

Impeller for Cummins 4BT Marine Raw Water Pump

Flexible Impeller

• Size: 2 9/16" diameter x 1 5/8" length

• Material: Flexible neoprene vanes

• Function: Creates vacuum pressure to pull seawater through the system

• Replacement Interval: Every 100-200 hours of use or annually

The impeller is the lifeblood of any marine raw water system. Even small wear or damage to an impeller's vanes can significantly reduce flow and lead to dangerous engine overheating.

Gaskets and Seals

Gasket for Mounting the Raw Water Pump

• Ensures a secure, leak-proof seal when installing a new pump

• High-temperature marine-grade material

O-Ring Gasket Seals for Heat Exchanger

• Usage: 2 required per engine

• Fitment: 4B, 4BT, 4BTA, 6B, 6BT, 6BTA engines

• Prevents saltwater or coolant leaks between exchanger components

Heat Exchanger Gasket Seal (3910343)

• Diameter: 4"

• Provides sealing between end caps and heat exchanger body

Heat Exchanger for Cummins 4BT Marine Engines

New Heat Exchanger for 4B3.9, 4BT3.9, 4BTA3.9

• Material: Copper-nickel tubes, bronze body

• Purpose: Transfers heat from coolant to seawater without fluid mixing

• Compatibility: Marine cooling systems on Cummins B Series

Replacing or upgrading your heat exchanger helps protect the engine block and head from heat-related stress and corrosion.

Zinc Anodes for Corrosion Control

Zinc for Heat Exchanger and Aftercooler

• Size: NPT 1/2", 2" zinc

• Prevents galvanic corrosion of brass, copper, and bronze components

Zinc for Fuel and Oil Coolers

• Size: NPT 3/8", 1" zinc

• Protects heat exchangers and oil coolers from electrolysis damage

Zincs are sacrificial anodes designed to corrode instead of your expensive cooling system. Check monthly and replace when 50% depleted.

Intake Water Strainers

1" Pipe Size

• 9.5" height x 5.5" width

• Compact design for tight spaces

1.5" Pipe Size

• 11.5" height x 7.25" width

2" Pipe Size

• 16" height x 7.5" width

2.5" Pipe Size

• Heavy-duty size for large-volume systems

• 16" height x 7.5" width

These strainers keep sand, shells, seaweed, and debris from damaging your pump impeller or clogging the exchanger.

Temperature Switch

Marine Temperature Switch (5146080)

• Activation Temp: 205°F

• Thread Size: 1/2" NPT

• Suitable for Cummins, Detroit Diesel, Caterpillar

• Alerts or shuts down engine at high temperature thresholds

Silicone Coolant Hoses

Available Sizes (All 1 Foot Lengths)

• 1"

• 1 3/4"

• 1 7/8"

• 2"

• 2 1/8"

• 2 1/4"

• 2 3/8"

• 2 1/2"

• 2 3/4"

• 3"

• 3 1/2"

• 4"

Marine-grade silicone hoses offer superior resistance to UV, salt, heat, and pressure compared to standard rubber hoses.

Hose Clamps for Marine Cooling Systems

Sizes and Effective Ranges

• 10H Clamp: 9/16" – 1 1/16"

• 5104592: 1" – 1.5"

• 4920417: 13/16" – 1 3/4"

• 3412320: 11/16" – 1 1/4"

• 3922846: 1 5/16" – 2 1/4"

• 3922847: 1 9/16" – 2 1/2" and 2 5/16" – 3"

All clamps are stainless steel and corrosion-resistant, designed for high-vibration, high-moisture marine engine bays.

Impeller Puller Tool

Universal Impeller Puller

• Prevents damage to impeller blades and pump housing during removal

• Saves time during routine service and emergency repairs

Marine Cooling System Maintenance Tips

• Replace impeller annually or after 100–200 hours

• Inspect and replace zincs monthly

• Flush heat exchanger annually to remove scale

• Replace hoses showing soft spots or swelling

• Tighten or replace clamps showing rust or thread wear