Audi A4 B9 Thermostat Housing Coolant Regulator 2.0 TDI DEUA 04L121113D

Audi A4 B9 Thermostat Housing Coolant Regulator 2.0 TDI DEUA is a component from the Thermostats and housings group, designed for the diesel engine cooling system. It is responsible for the stable routing of coolant and interaction with the thermostat, which translates into the correct operating temperature of the power unit and safe operating conditions.

Specifications and technical data

• SKU: 04L121113D
• Mark: Audi
• Condition: Used
• OEM Part Number: 04L121113D
• Substitutable numbers: 04L121113D, 04L 121 113 D
• Fuel type: Diesel
• Part type: Thermostat Housing
• Category: Thermostats & Housings

Purpose and function in the cooling system

The thermostat housing in the 2.0 TDI DEUA engine plays a key role in precisely directing the flow of coolant between the engine block and other system components. A correctly selected part ensures:

• stable maintenance of the diesel engine's operating temperature,
• interaction with the thermostat without delays in opening and closing the circuit,
• reduction of the risk of overheating or undercooling of the power unit,
• proper operation of accessories associated with the cooling system.

Thanks to a design consistent with the solutions used by Audi, the housing maintains the correct connection geometry and positioning relative to the engine, which facilitates installation and subsequent maintenance.

Technical characteristics and compatibility

The presented thermostat housing has been designed to work with a diesel engine, which means it is adapted to the specific operating conditions of a diesel unit – higher thermal loads and longer service cycles. The component's design takes into account:

• proper routing of coolant channels,
• sensor locations and ports provided for the specific engine variant,
• body rigidity to limit thermal deformation,
• compatibility with factory cooling system accessories.

Selecting a housing compatible with the 2.0 TDI DEUA unit allows for maintaining the operating parameters specified by the vehicle manufacturer, which is particularly important in modern engines with advanced temperature control.

Benefits of using an original thermostat housing

Using a component from the Audi parts group provides a number of practical benefits in daily operation. The most important include:

• secure fit to the cooling system – preservation of factory mounting points and connection diameters,
• consistency with the factory engine temperature control concept,
• reduction of the risk of leaks resulting from inaccurate fitment,
• easier diagnostics and service due to compliance with manufacturer documentation.

For users considering the choice between an original part and a replacement, the following guide may be useful: 5 reasons why a used OEM part is a better choice than a replacement, which discusses practical differences using examples of popular models.

Condition of the component and installation aspects

The thermostat housing is offered as a part from the secondary market, which allows for an economical repair of the cooling system while maintaining a design consistent with factory solutions. Before installation, a standard service procedure is recommended, including checking the contact surfaces, seals, and coolant supply hoses.

A properly selected and installed housing supports even engine warm-up, stable operation across the full load range, and correct functioning of systems related to operating temperature, which translates into the durability of the power unit and vehicle comfort.

Expanding the cooling system in Audi

If you are planning a comprehensive repair or upgrade of the engine area in your Audi and need other components from the same group, such as additional housings, bodies, or modules related to temperature regulation, check the available parts in the Audi Thermostats and housings category.