Dorman 902-5903 Engine Coolant Thermostat Housing Assembly

Engine Coolant Thermostat Housing Assembly

Dorman 902-5903 is a replacement engine coolant thermostat housing assembly built for specified Mercedes-Benz and Dodge Sprinter applications. It uses a metal housing with an included gasket and thermostat, and it is engineered to match the fit and durability of the original housing while handling repeated temperature swings.

Compatible With Mercedes-Benz G500, G550, CL500, E250, E500, GL450, GL500, GL550, SL500, SL550, CLS350, CLS500, E550, ML500, ML550, S450, S500, S550, CL550, E300, and R550 applications, as well as Dodge Sprinter 2500 and Sprinter 3500 models in the listed years.

• Metal thermostat housing construction for strength and heat resistance
• Includes gasket, thermostat, and sensor for a complete service replacement
• Thermostat opening temperature: 212 degrees F
• One outlet port with two mounting holes for the specified OE-style layout
• Natural finish housing with integrated cover design
• Cross-reference part numbers include Gates 34718 and Motorad 669-212

Detailed Product Overview

This Dorman thermostat housing assembly is designed for direct replacement on 2007-2015 Mercedes-Benz G500 and G550, 2007-2012 Mercedes-Benz CL500, 2007-2012 Mercedes-Benz GL450, GL500, and GL550, 2007-2012 Mercedes-Benz SL500 and SL550, 2007-2011 Mercedes-Benz S500 and S550, and other listed applications. It also covers 2007-2008 Dodge Sprinter 2500 and Sprinter 3500 models. The housing is built from metal and sized to match the original flange and bolt-hole layout for the specified vehicles, helping restore proper coolant routing and thermostat function.

Dorman 902-5903 is a practical choice when servicing a leaking, warped, or heat-damaged thermostat housing on Mercedes-Benz G500, GL550, or Sprinter cooling systems. The included thermostat and gasket support a complete repair at the housing location, while the 212 degrees F thermostat opening temperature matches the listed application requirements.

Common Problems This Part Can Address

• Coolant seepage at the thermostat housing gasket surface
• Cracked or warped housing from repeated heat cycling
• Thermostat sticking open or closed and affecting engine temperature control
• Sensor-related service needs at the housing assembly
• Loss of proper coolant flow through the thermostat housing area

Installation Notes and Tips

Confirm the vehicle year, make, model, and engine configuration against the listed fitment before installation. Inspect the mating surfaces, coolant passages, and adjacent hoses for wear or contamination before assembly. Because mounting hardware is not included, reuse or source the correct fasteners as needed for the application. Bleed the cooling system carefully after installation to remove trapped air and verify normal operating temperature.

Quality Assurance

Dorman designs this replacement thermostat housing assembly to match the fit and durability of the original part on the specified vehicles and to withstand extreme temperature changes for extended service life.