Engine Coolant Thermostat Housing Cover

This Genuine engine coolant thermostat housing cover, part number 078121121K, is a direct-fit cooling system component for select Audi and Volkswagen applications. It is used on vehicles such as the Audi A6, Audi A6 Quattro, Audi Allroad Quattro, and Volkswagen Passat across the listed model years.

Key Features

• Genuine OE-style engine coolant thermostat housing cover
• Part number: 078121121K
• Fits select 2001-2005 Audi and Volkswagen models
• Supports thermostat housing service in the cooling system
• Built for direct replacement on listed applications

Fitment Details

• Fits 2001-2005 Audi Allroad Quattro, N/A.
• Fits 2002-2004 Audi A6 Quattro, N/A.
• Fits 2001 Audi A6, N/A, from 6/00; VIN 4B.1.007 001.
• Fits 2001 Audi A6 Quattro, N/A, from 6/00; VIN 4B.1.007 001.
• Fits 2002-2005 Volkswagen Passat, N/A.
• Fits 2001 Volkswagen Passat, N/A, from 3/01; VIN 3B.1.050 000.

What It Helps Address

• Coolant leaks at the thermostat housing cover
• Cracked or warped housing cover surfaces
• Cooling system service on the thermostat assembly
• Fitment issues when replacing a worn OE cover

Installation Notes

Verify engine code, VIN breakpoints, and model year before ordering. This part number 078121121K is listed for specific Audi A6, Audi A6 Quattro, Audi Allroad Quattro, and Volkswagen Passat applications, so match the vehicle details exactly to the fitment notes. Inspect the thermostat housing and sealing surfaces during service and replace any damaged mating components as needed.

Quality Assurance

Genuine parts are built to OE specifications for the listed applications. This part cross-references no additional part numbers in the provided data.