Parts for Detroit Diesel 371 Non-Turbo - (4 Valve Head Type) - Marine Water Pump Section

Parts for Detroit Diesel 3-71 Non-Turbo (4 Valve Head Type) - Marine Water Pump Section

The Detroit Diesel 3-71 Non-Turbo engine, equipped with a 4-valve head design, is one of the most enduring marine engines in history. Known for its rugged reliability, smooth torque delivery, and ease of service, this compact 3-cylinder inline engine powered countless workboats, fishing vessels, and small tugs across decades. A critical component that ensures its longevity and efficient performance is its marine cooling system—specifically, the raw water pump and related components that manage the circulation of seawater through the engine and heat exchanger system.

At Diesel Pro Power, we specialize in delivering premium-quality marine water pumps and complete cooling system parts for the Detroit Diesel 3-71 Non-Turbo. Each item in our catalog is carefully selected to ensure OEM-level performance, durability in saltwater environments, and fast installation compatibility with Detroit Diesel marine configurations. Below is a detailed overview of our most popular and in-stock components for the Detroit Diesel 3-71 Non-Turbo (4 Valve Head Type) engine.

Marine Water Pump for Detroit Diesel 3-71 Non-Turbo Engines

The marine raw water pump is the heart of your 3-71’s cooling system. Its primary function is to pull seawater from the hull intake, circulate it through the heat exchanger, and discharge the warmed water overboard—maintaining a stable engine temperature under all operating conditions.

Our Detroit Diesel marine water pump is a bidirectional pump, meaning it can rotate in either direction—clockwise or counterclockwise. This versatility makes it ideal for left-hand or right-hand engine configurations, a key feature for twin-engine setups in marine applications.

• Port Type: 1-inch flange connection

• Includes: Drive gear and mounting adapter

• Material: Marine-grade bronze housing with corrosion-resistant internals

• Impeller Type: Flexible neoprene impeller with 10 blades for smooth, consistent flow

Each new pump comes fully assembled and ready for installation. It’s designed to deliver efficient cooling flow, long impeller life, and minimal maintenance—ensuring your Detroit Diesel 3-71 operates at the correct temperature, even in tropical or high-load environments.

Marine Water Pump Gaskets and Seals

A marine water pump’s performance depends as much on proper sealing as on its internal mechanics. Diesel Pro Power supplies all gaskets and seals required for a complete marine pump installation on the Detroit Diesel 3-71.

Marine Water Pump Gasket

This gasket ensures a watertight seal between the pump housing and the mounting surface, preventing leaks that could reduce cooling efficiency or cause corrosion around the housing.

Dual Water Port Gasket (Inlet and Outlet)

Each 3-71 water pump uses two of these gaskets—one for the inlet and one for the outlet—ensuring that seawater enters and exits the pump efficiently without leaks. Proper gasket replacement during maintenance keeps your engine protected from air intrusion and uneven cooling.

Marine Water Pump Seal

Used on pumps with 1-inch inlet/outlet ports and 2-inch impeller height, this precision-engineered seal prevents water from leaking into the drive assembly. It is designed to withstand high-pressure marine conditions and saltwater exposure.

Impeller for Detroit Diesel 3-71 Marine Water Pump

The impeller is the moving component that drives seawater circulation. Our flexible impeller features 10 blades and a 12-spline drive, optimized for smooth flow and minimal vibration.

• Diameter: 2 1/2 inches

• Height: 2 inches

• Material: Neoprene rubber reinforced with marine-grade hubs

A well-maintained impeller ensures proper engine cooling. We recommend inspecting and replacing impellers annually or every 500 hours, whichever comes first, to prevent overheating or uneven flow. Diesel Pro Power provides impellers that are fully compatible with both Detroit Diesel and Volvo Penta marine water pumps, making them ideal for mixed fleet operators.

Thermostat and Related Components

The Detroit Diesel 3-71 thermostat plays a crucial role in regulating coolant flow between the engine block and heat exchanger. At 173°F (approximately 78°C), this thermostat opens to maintain ideal engine temperature for both performance and longevity.

• Thermostat Housing Gasket ensures a tight seal between the thermostat and housing.

• Thermostat Gasket maintains pressure balance and prevents coolant seepage under high load.

Replacing these components together ensures consistent temperature regulation, optimal fuel combustion, and reduced engine wear.

Heat Exchanger and Cooling Tank Components

The heat exchanger serves as the interface between seawater and engine coolant, transferring heat from the closed-loop system without direct contact between fluids.

Marine Heat Exchange Tank

A used but fully tested Detroit Diesel 3-71 heat exchanger tank is available, designed for direct compatibility with 3-71, 4-71, and 6-71 marine engines. It maintains proper thermal balance under continuous marine duty and can be refurbished easily using Diesel Pro Power’s gasket kits and seals.

Heat Exchanger Core

This core fits perfectly within the heat exchanger housing, allowing maximum surface area for heat transfer. Built with corrosion-resistant metals, it ensures long-lasting cooling efficiency in saltwater environments.

Heat Exchanger Gasket Kit

This comprehensive gasket set includes all seals necessary for disassembling and resealing the marine cooling system. It fits Series 53, 71, and 92 engines, making it ideal for operators maintaining multiple Detroit Diesel models.

Oil Cooler and Accessory Sealing Components

The Oil Cooler Water Inlet Gasket ensures no seawater leakage where the pump feeds cooling water to the oil cooler. Proper sealing in this area is vital for engine longevity since leaks can cause both overheating and oil contamination.

The Adapter Gasket and Flywheel Housing Gasket also play key roles in preventing water intrusion into mechanical components. Each gasket is built with marine-grade composite materials to resist compression and heat.

Accessory Drive Coupling

This 21-tooth coupling connects the marine water pump or accessory drive to the Detroit Diesel engine shaft. Built from hardened steel, it ensures precise power transmission and minimal vibration, critical for keeping alignment in marine applications. Diesel Pro Power’s couplings are precision-machined to OEM tolerances for a perfect fit.

Zinc Anodes for Marine Cooling Systems

Zinc anodes are sacrificial metals that protect marine engine components from electrolysis and corrosion. Diesel Pro Power carries multiple zinc configurations compatible with Detroit Diesel 3-71 engines:

• For Marine Water Pumps and Heat Exchangers: Brass plug NPT 1/2", zinc length 2"

• For Fuel and Oil Coolers: Brass plug NPT 3/8" or 1/8" configurations

Replacing zincs regularly—typically every season or 100 hours—preserves your pump housings, coolers, and heat exchangers from galvanic corrosion.

Radiator Components

The radiator gaskets and caps ensure that your cooling system maintains correct pressure and leak-free operation. The 7 PSI radiator cap helps maintain coolant pressure for efficient heat transfer and prevents boiling under load.

The Radiator Cap Neck serves as the mounting base for the radiator cap, made from precision-cast metal to ensure durability against temperature fluctuations and vibration common in marine use.

Coolant Hoses and Clamps

Diesel Pro Power offers a complete selection of marine-grade silicone coolant hoses in various diameters (1” to 4”). Silicone hoses outperform standard rubber hoses in marine applications by resisting salt, oil, and heat degradation.

Each hose is reinforced with fabric for strength and flexibility. Clamps for each size range are also available, ensuring a secure and leak-free installation.

• Clamp Sizes Available:

• Range 9/16"–1 1/16"

• Range 13/16"–1 3/4"

• Range 1 5/16"–2 1/4"

• Range 2 5/16"–3"

Every hose and clamp combination ensures your cooling lines remain sealed under vibration and heat cycling.

Additional Marine Cooling Accessories

Intake Water Strainer

The intake strainer filters debris from seawater before it enters the raw water pump. Our 1.5” pipe size strainer features a stainless-steel screen and durable housing, ensuring long service life even in sediment-heavy waters.

Detroit Diesel Engine Paint

Detroit Diesel Green paint restores the authentic factory finish of your 3-71 engine. It also provides corrosion resistance to metallic surfaces exposed to salt air and humidity. Available for ground shipping within the USA and Canada.

Why Buy Detroit Diesel 3-71 Marine Water Pump Parts from Diesel Pro Power

With over 40,000 satisfied customers worldwide, Diesel Pro Power is the trusted source for Detroit Diesel marine parts. Our selection of new, rebuilt, and OEM-equivalent marine water pumps and cooling components is unmatched in quality and reliability.

Here’s why marine professionals choose Diesel Pro Power:

• Specialization: We focus on Detroit Diesel marine engines, ensuring accurate fitment and technical precision.

• Fast Global Shipping: We deliver to over 180 countries with same-day dispatch for most orders.

• Comprehensive Inventory: From water pumps to heat exchangers, we carry every component you need to service your Detroit Diesel 3-71 cooling system.

• Expert Support: Our technicians are Detroit Diesel specialists who can assist with configuration, rotation direction, and compatibility questions.

• Guaranteed Quality: Each component is tested or inspected for proper function, ensuring peace of mind during installation.