Motorad 989-189 Engine Coolant Thermostat Housing Assembly

Integrated Housing Thermostat for Mercedes-Benz Cooling Systems

Motorad 989-189 is an integrated housing thermostat assembly built for OE-style cooling system service. It combines the thermostat, housing, and seal in a single replacement part for select Mercedes-Benz AMG applications, including G55 AMG, SL55 AMG, CL55 AMG, CLS55 AMG, E55 AMG, and S55 AMG models.

The Integrated Housing Thermostat line is focused on direct-fit cooling components manufactured to OEM specifications and processes. This Motorad thermostat assembly uses aluminum, steel, and copper construction with a copper case and wax compound for quick response to coolant temperature changes.

Key Features

• Part number: 989-189
• Integrated housing thermostat assembly for engine coolant control
• OE supplier manufacturing with OEM quality materials and safety standards
• 189 degree F thermostat temperature rating
• Aluminum, steel, and copper construction with silver finish
• Gasket/seal included with rubber O-ring seal
• 1 outlet port, 2 bolt holes
• Bypass diameter: 1.69 in; bypass length: 0.99 in
• Outlet diameter: 1.67 in

Detailed Description

Motorad 989-189 is an engine coolant thermostat housing assembly engineered for vehicles that require a 189F OE-specified thermostat setting. The integrated design helps simplify replacement by combining the thermostat, housing, and seal into one service part. Built with copper, aluminum, and steel materials, it is made to handle demanding automotive cooling system conditions while maintaining accurate temperature control. This part cross-references Four Seasons 59898 for the same application.

Compatible With 2005-2011 Mercedes-Benz G55 AMG, 2003-2008 Mercedes-Benz SL55 AMG, 2003-2006 Mercedes-Benz CL55 AMG, 2006 Mercedes-Benz CLS55 AMG, 2003-2006 Mercedes-Benz E55 AMG, and 2003-2006 Mercedes-Benz S55 AMG. Use Motorad 989-189 when replacing a thermostat housing assembly on these Mercedes-Benz AMG models and when the OE temperature specification is 189F.

Common Issues This Part Can Address

• Coolant temperature regulation problems caused by a worn thermostat
• Leaks at the thermostat housing or seal area
• Slow thermostat response during warm-up or temperature changes
• Cooling system service needs on Mercedes-Benz AMG engines with integrated housing design
• Replacement of a damaged or aging thermostat housing assembly

Installation Notes and Tips

Verify engine application, thermostat temperature rating, and housing configuration before installation. This assembly includes a gasket/seal, but mounting hardware and installation tools are not included. Inspect the mating surfaces, clean the coolant passages, and replace coolant as required by the vehicle service procedure. Confirm the bypass and outlet dimensions match the original part before final assembly.

Quality Assurance

Manufactured by an OE supplier using OEM quality materials and processes, this thermostat housing assembly is built to meet the demands of modern cooling systems. Motorad 989-189 is produced to OE specifications for fit and temperature control consistency.