Motorad 975-198 Engine Coolant Thermostat Housing Assembly

Integrated Thermostat Housing for Mercedes-Benz Cooling Systems

Motorad 975-198 is an integrated engine coolant thermostat housing assembly built to OE specifications for select Mercedes-Benz diesel and gasoline applications. It combines the thermostat, housing, and seal in one service part for a direct replacement on models such as the Mercedes-Benz GL350, ML350, and R350.

The Motorad Integrated Housing Thermostat line focuses on OE-style fit, temperature control, and durable construction for demanding cooling systems. This 198 degree thermostat housing assembly uses aluminum, stainless steel, and copper materials, with a rubber seal, bleeder hole, and jiggle pin for service-friendly coolant bleeding and temperature response.

Key Features

• Part number: 975-198
• Integrated engine coolant thermostat housing assembly
• Opening temperature: 198 Deg. F
• Bleeder hole and jiggle pin included
• Gasket/seal included; rubber seal material
• 4 bolt holes and 1 outlet port
• Outlet diameter: 1.90 in
• Constructed from aluminum, stainless steel, and copper
• Silver finish
• OE supplier manufacturing with OEM specifications and processes

Product Details

Motorad 975-198 is engineered as an OE-style thermostat housing replacement for vehicles that require a 198 degree opening temperature. The copper case and wax compound are used to respond quickly to coolant temperature changes, helping maintain stable engine operating temperature under normal driving and load conditions. This part cross-references Dorman OE Solutions 902-5189 for the same application.

Compatible With Mercedes-Benz GL350, Mercedes-Benz ML350, Mercedes-Benz R350, Mercedes-Benz S350, and Mercedes-Benz GLS350d applications that call for an integrated housing thermostat at 198F. Search terms such as Mercedes-Benz GL350 thermostat housing assembly, ML350 engine coolant thermostat housing, and 198 degree integrated thermostat for Mercedes-Benz diesel cooling systems align with this part.

Common Problems This Part Can Address

• Coolant temperature staying below or above the specified operating range
• Thermostat housing leaks at the seal or mating surface
• Delayed thermostat response during warm-up
• Cooling system service needs on integrated thermostat designs
• Check engine concerns related to thermostat performance

Installation Notes and Tips

Verify the OE-specified 198F temperature and match the outlet diameter, bolt-hole count, and housing style before installation. Inspect the mating surface, replace worn coolant as needed, and confirm the bleeder hole and jiggle pin are oriented correctly during fill and bleed procedures. This assembly does not include bolts or mounting hardware.

Fits 2017 Mercedes-Benz GLS350d, N/A; Fits 2013-2016 Mercedes-Benz GL350, N/A; Fits 2012-2015 Mercedes-Benz ML350, N/A; Fits 2013 Mercedes-Benz R350, N/A; Fits 2012-2013 Mercedes-Benz S350, N/A.

Quality Assurance

Motorad manufactures this integrated housing thermostat with OEM-quality materials and OE supplier processes to meet the demands of automotive cooling systems. The design follows OEM specifications for fit and temperature control, supporting consistent service replacement on Mercedes-Benz GL350, ML350, and related applications.