Gates 34859 Engine Coolant Thermostat

Integrated Thermostat Housing for Volvo Cooling Systems

Gates 34859 is an integrated housing thermostat built for precise engine coolant temperature control in select Volvo applications. It is an OE-performance replacement for vehicles that use a thermostat and housing assembly together, helping maintain stable operating temperature in daily driving.

Compatible With Volvo V60, V60 Cross Country, XC60, XC70, S60, V40 Cross Country, C30, C70, S40, and V50 applications listed below. This part cross-references Dorman OE Solutions 902-5864 for the same application.

Key Features

• Integrated Housing Thermostat design for applications that use a combined thermostat and housing assembly
• Start-to-open temperature: 194°F / 90°C
• OE Performance rating for factory-style temperature regulation
• Three bolt holes for secure mounting
• Jiggle pin weep hole and jiggle pin/check valve included in the design
• One seal specified for the assembly
• Outlet dimensions: 1.09 in, .80 in, and .81 in inside diameter; 1.26 in, .91 in, and .97 in outside diameter

Product Details

Gates Integrated Housing Thermostat 34859 is engineered for modern cooling systems that rely on an integrated thermostat housing rather than a separate thermostat. Gates focuses on aftermarket thermostat solutions for these OE-style assemblies, giving Volvo owners a direct replacement option that supports accurate coolant flow control and consistent engine operating temperature. This part number 34859 is listed for multiple Volvo models, including 2013-2015 Volvo S60, 2015-2016 Volvo V60, and 2016 Volvo XC60 and XC70 applications.

Common Cooling Issues This Part Can Address

• Engine running too cool or too warm due to thermostat regulation problems
• Coolant temperature fluctuation during stop-and-go or highway driving
• Leak points associated with a worn thermostat housing assembly
• Check engine light concerns tied to coolant temperature performance
• Service needs on Volvo cooling systems that use an integrated thermostat housing

Installation Notes and Tips

• Verify the vehicle’s engine code and cooling system layout before ordering, since integrated housings are application-specific.
• Inspect mating surfaces and coolant passages carefully during replacement.
• Confirm the 194°F / 90°C opening temperature matches the OE specification for the vehicle.
• Use the listed fitment notes for each Volvo model, including applications that specify housing inclusion and seal included.
• Bleed the cooling system according to factory service procedures after installation.

Quality Assurance

Gates develops integrated thermostat housing solutions to meet OE-style performance expectations and temperature control requirements. The 34859 is built as an OE-performance replacement for select Volvo cooling systems, including Volvo V60, Volvo S60, and Volvo XC60 applications listed in the fitment data.