Audi / Volkswagen Aluminum Thermostat Housing 078121121J
OEM Part #: 078-121-121-J (078121121J)
This page covers one exact OEM part number. Every unit we stocked has sold.
We may be able to get another
Used OEM parts are one-of-a-kind. We sometimes get another when we dismantle a matching vehicle, but we can’t say when — browse what’s in stock now:
Other Thermostat Housing that may fit your vehicle
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The Aluminum Thermostat Housing is a critical component located in the engine bay, facilitating the flow of coolant within the cooling system of various Audi and Volkswagen models. This OEM part, identified by part numbers 078121121F, 078121121D, 078121121K, and Bosch number 078121121J, ensures precise temperature regulation by directing coolant from the engine to the radiator. Common failure scenarios include leaks, cracks, or corrosion, which can lead to overheating and engine damage. Compatible vehicles include the Audi A4, A6, and S4 (1995-2004) and the Volkswagen Passat (1998-2005). This genuine part guarantees factory-original fitment and performance, directly sourced from salvage vehicles.
Specifications
| Fits Vehicle Model | 90, A4, A6, Allroad, Cabriolet, Passat, S4 |
| Fits Vehicle Make | Audi, Volkswagen |
| OEM Part No | 078-121-121-J (078121121J) |
| Compatible OEM Part No | 078-121-121-F, 078-121-121-D, 078-121-121-K |
| Category | Radiator / Coolant |
Compatible Vehicles
Fits 90 vehicle configurations across 2 makes, 1995-2005.
Check your specific vehicle before ordering.
This list shows year, make, and model. Some years have multiple trims or
engines that use different parts, and individual listings may have
additional fitment notes (e.g. “with sunroof only”). Review
the full variant list below, or
message us with your VIN
and we’ll confirm the match.
View all 90 vehicle configurations — 34 with fitment notes
| Year | Make | Model | Trim | Engine | Note |
|---|---|---|---|---|---|
| 1995 | Audi | 90 | Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 025821 |
| 1995 | Audi | 90 | Quattro Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 025821 |
| 1995 | Audi | A6 | Wagon | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 026715 |
| 1995 | Audi | A6 | Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 026715 |
| 1995 | Audi | A6 | Quattro Wagon | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 026715 |
| 1995 | Audi | A6 | Quattro Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 026715 |
| 1995 | Audi | Cabriolet | Convertible | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Greater Than 001303 |
| 1996 | Audi | A4 | Sedan | 2.8L V6 | |
| 1996 | Audi | A4 | Quattro Sedan | 2.8L V6 | |
| 1996 | Audi | A6 | Wagon | 2.8L V6 | |
| 1996 | Audi | A6 | Sedan | 2.8L V6 | |
| 1996 | Audi | A6 | Quattro Wagon | 2.8L V6 | |
| 1996 | Audi | A6 | Quattro Sedan | 2.8L V6 | |
| 1996 | Audi | Cabriolet | Convertible | 2.8L V6 | |
| 1997 | Audi | A4 | Sedan | 2.8L V6 | |
| 1997 | Audi | A4 | Quattro Sedan | 2.8L V6 | |
| 1997 | Audi | A6 | Wagon | 2.8L V6 | |
| 1997 | Audi | A6 | Sedan | 2.8L V6 | |
| 1997 | Audi | A6 | Quattro Wagon | 2.8L V6 | |
| 1997 | Audi | A6 | Quattro Sedan | 2.8L V6 | |
| 1997 | Audi | Cabriolet | Convertible | 2.8L V6 | |
| 1998 | Audi | A4 | Wagon | 2.8L V6 | |
| 1998 | Audi | A4 | Sedan | 2.8L V6 | |
| 1998 | Audi | A4 | Quattro Wagon | 2.8L V6 | |
| 1998 | Audi | A4 | Quattro Sedan | 2.8L V6 | |
| 1998 | Audi | A6 | Sedan | 2.8L V6 | |
| 1998 | Audi | A6 | Quattro Wagon | 2.8L V6 | |
| 1998 | Audi | A6 | Quattro Sedan | 2.8L V6 | |
| 1998 | Audi | Cabriolet | Convertible | 2.8L V6 | |
| 1999 | Audi | A4 | Sedan | 2.8L V6 | |
| 1999 | Audi | A4 | Quattro Wagon | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 1999 | Audi | A4 | Quattro Sedan | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 1999 | Audi | A6 | Sedan | 2.8L V6 | |
| 1999 | Audi | A6 | Quattro Wagon | 2.8L V6 | |
| 1999 | Audi | A6 | Quattro Sedan | 2.8L V6 | |
| 2000 | Audi | A4 | Sedan | 2.8L V6 | |
| 2000 | Audi | A4 | Quattro Wagon | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 2000 | Audi | A4 | Quattro Sedan | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 2000 | Audi | A6 | Sedan | 2.8L V6 | |
| 2000 | Audi | A6 | Quattro Wagon | 2.8L V6 | |
| 2000 | Audi | A6 | Quattro Sedan | 2.7L V6 Turbo | |
| 2000 | Audi | A6 | Quattro Sedan | 2.8L V6 | |
| 2000 | Audi | S4 | Sedan | 2.7L V6 Turbo | For Vehicles with Engine Code(s) APB |
| 2001 | Audi | A4 | Sedan | 2.8L V6 | |
| 2001 | Audi | A4 | Quattro Wagon | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 2001 | Audi | A4 | Quattro Sedan | 2.8L V6 | For Vehicles with Engine Code(s) AHA, ATQ |
| 2001 | Audi | A6 | Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Less Than 007000 |
| 2001 | Audi | A6 | Quattro Wagon | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Less Than 007000 |
| 2001 | Audi | A6 | Quattro Sedan | 2.7L V6 Turbo | For Vehicles Where Last 6 Digits of VIN Number are Less Than 007000 |
| 2001 | Audi | A6 | Quattro Sedan | 2.8L V6 | For Vehicles Where Last 6 Digits of VIN Number are Less Than 007000 |
| 2001 | Audi | Allroad | Quattro Wagon | 2.7L V6 Turbo | |
| 2001 | Audi | S4 | Wagon | 2.7L V6 Turbo | For Vehicles with Engine Code(s) APB |
| 2001 | Audi | S4 | Sedan | 2.7L V6 Turbo | For Vehicles with Engine Code(s) APB |
| 2002 | Audi | A6 | Quattro Sedan | 2.7L V6 Turbo | |
| 2002 | Audi | Allroad | Quattro Wagon | 2.7L V6 Turbo | |
| 2002 | Audi | S4 | Wagon | 2.7L V6 Turbo | For Vehicles with Engine Code(s) APB |
| 2002 | Audi | S4 | Sedan | 2.7L V6 Turbo | For Vehicles with Engine Code(s) APB |
| 2003 | Audi | A6 | Quattro Sedan | 2.7L V6 Turbo | |
| 2003 | Audi | Allroad | Quattro Wagon | 2.7L V6 Turbo | |
| 2004 | Audi | A6 | Quattro Sedan | 2.7L V6 Turbo | |
| 2004 | Audi | Allroad | Quattro Wagon | 2.7L V6 Turbo | |
| 2005 | Audi | Allroad | Quattro Wagon | 2.7L V6 Turbo | |
| 1998 | Volkswagen | Passat | Sedan | 2.8L V6 | |
| 1998 | Volkswagen | Passat | Wagon | 2.8L V6 | |
| 1999 | Volkswagen | Passat | Sedan | 2.8L V6 | |
| 1999 | Volkswagen | Passat | Wagon | 2.8L V6 | |
| 2000 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | |
| 2000 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | |
| 2000 | Volkswagen | Passat | Sedan | 2.8L V6 | |
| 2000 | Volkswagen | Passat | Wagon | 2.8L V6 | |
| 2001 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | |
| 2001 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | |
| 2001 | Volkswagen | Passat | Sedan | 2.8L V6 | |
| 2001 | Volkswagen | Passat | Wagon | 2.8L V6 | |
| 2002 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | |
| 2002 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | |
| 2002 | Volkswagen | Passat | Sedan | 2.8L V6 | |
| 2002 | Volkswagen | Passat | Wagon | 2.8L V6 | |
| 2003 | Volkswagen | Passat | Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2003 | Volkswagen | Passat | Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2003 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2003 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2004 | Volkswagen | Passat | Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2004 | Volkswagen | Passat | Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2004 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2004 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2005 | Volkswagen | Passat | 4 Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2005 | Volkswagen | Passat | 4 Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2005 | Volkswagen | Passat | Sedan | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |
| 2005 | Volkswagen | Passat | Wagon | 2.8L V6 | For Vehicles with Engine Code(s) ATQ |