Dorman 902-5189 Engine Coolant Thermostat Housing Assembly

Engine Coolant Thermostat Housing Assembly

Dorman 902-5189 is a replacement engine coolant thermostat housing assembly built to match the fit and durability of the original housing on specified Mercedes-Benz diesel applications. It features a metal housing, a gasket and seal, and an integrated thermostat set to open at 198 degrees F for direct service replacement.

Compatible With Mercedes-Benz GLS350d, GL350, GLE350d, ML350, ML400, R350, and S350 applications listed below, this housing is designed for vehicles that use an integrated cover style. The Dorman 902-5189 part number is also referenced by Motorad 975-198 and OE-style cross reference 6422001915.

Key Features

• Metal thermostat housing with natural finish
• Integrated thermostat included, opening at 198 degrees F
• Gasket and seal included for the housing interface
• Three mounting holes with OE-style flange dimensions
• Single outlet port configuration
• No bleeder hole
• Fits diesel Mercedes-Benz cooling system applications with integrated cover design

Detailed Description

This thermostat housing assembly is engineered for Mercedes-Benz cooling system service where the thermostat and housing are serviced together. The metal construction helps maintain dimensional stability through repeated heat cycling, while the included thermostat and seal simplify replacement of worn or leaking original components. Dorman 902-5189 is sized with a 1.72-inch inside diameter, 3.522-inch flange length, 2.86-inch flange width, and 0.319-inch flange thickness to match the original housing layout on the listed vehicles.

Vehicle coverage includes 2017 Mercedes-Benz GLS350d; 2013-2016 Mercedes-Benz GL350; 2016 Mercedes-Benz GLE350d; 2012-2015 Mercedes-Benz ML350; 2015 Mercedes-Benz ML400; 2011-2013 Mercedes-Benz R350; 2012-2013 Mercedes-Benz S350; 2011-2012 Mercedes-Benz GL350; and 2011 Mercedes-Benz ML350. Use this part when servicing a Mercedes-Benz ML350 thermostat housing assembly, a GL350 engine coolant thermostat housing replacement, or a GLS350d cooling system repair that calls for the integrated cover style.

What It Helps Fix

• Coolant leaks at the thermostat housing or cover
• Temperature control issues from a worn thermostat
• Cracked, warped, or corroded original housing components
• Cooling system service needs on diesel Mercedes-Benz models
• Fitment problems caused by mismatched housing dimensions

Installation Notes

Confirm the vehicle’s engine code and cooling system configuration before installation, especially on Mercedes-Benz diesel models with heated or U42 diesel exhaust treatment notes. Transfer no mounting hardware unless your vehicle already uses reusable fasteners, since mounting hardware is not included. Inspect the mating surfaces, replace coolant as required by the service procedure, and verify the seal seats evenly before tightening the housing.

Quality Assurance

Dorman designs this replacement housing to match the fit and durability of the stock assembly on the listed applications and to withstand extreme temperature changes for extended service life. The part number 902-5189 is built as a regular-grade replacement for direct cooling system service on compatible Mercedes-Benz vehicles.