Gates 42178 Engine Water Pump with Fan Clutch

Gates 42178 Water Pump with Fan Clutch

The Gates 42178 is an engine water pump with fan clutch built for select Nissan applications. It combines a cast aluminum housing, stamped steel impeller, and accessory-belt drive layout for direct replacement service on listed vehicles.

Gates Water Pump (Standard) components are built with premium alloy materials and undergo seal, bearing, and leakage testing before release. This makes the Gates 42178 a practical OE-quality replacement for Nissan D21, Pathfinder, 720, 200SX, and 510 models that use the specified standard water pump configuration.

Key Features

• Cast aluminum housing for corrosion-resistant strength
• Stamped steel impeller with standard rotation
• Accessory belt drive style
• Fan clutch included for listed applications
• Pulley included
• Water pump and gasket included
• Timing belt driven: no
• Thermostat and housing not included
• Back housing not included

Detailed Description

This Gates 42178 water pump is engineered for Nissan cooling system service where a standard-rotation, accessory-belt-driven pump is required. It is listed for 1986-1989 Nissan D21, 1987-1988 Nissan Pathfinder, 1986 Nissan 720, 1983-1985 Nissan 720 with 5.25" fan bolt pattern, 1980-1983 Nissan 200SX with 5.25" fan bolt pattern, 1981-1983 Nissan 720 with fan clutch and 5.25" fan bolt pattern, 1978-1981 Nissan 510 with A.C. and 5.25" fan bolt pattern, 1980 Nissan 720 with A.C. and 5.25" fan bolt pattern, and 1977-1979 Nissan 200SX. The part number 42178 is also a useful reference when matching replacement cooling components for these Nissan platforms.

This part cross-references Airtex AW9031 and Dayco DP850 for the same application.

What It Helps Fix

• Coolant leaks from a worn pump seal or casting surface
• Overheating caused by reduced coolant circulation
• Noise from worn pump bearings
• Poor fan drive operation on applications using a fan clutch
• Cooling system service needs on Nissan D21, Pathfinder, 720, 200SX, and 510 models

Installation Notes and Tips

Verify the fan bolt pattern, accessory-belt drive setup, and whether the vehicle uses a fan clutch before ordering. Confirm that your application does not require a timing-belt-driven pump, since this unit is not timing-belt driven. Replace the gasket during installation and inspect the belt, pulley alignment, and mating surfaces before filling the cooling system.

Quality Assurance

Gates states that its water pumps are built from premium alloy materials and tested for seal and bearing function as well as leakage at both the casting and assembled pump level. The Water Pump (Standard) line is positioned as an OE-quality replacement option for service work on the listed Nissan applications.