Audi A4 B9 A5 F5 Water Coolant Cooling Hose Pipe 2.0 TDI 04L122157BT

Audi A4 B9 A5 F5 Water Coolant Cooling Hose Pipe 2.0 TDI is an original component from the Cooling system hoses and pipes group, designed for operation in the 2.0 TDI diesel engine cooling system. This used OEM component ensures proper coolant flow between the radiator and other system elements, supporting stable operating temperatures for the power unit.

Specifications and technical data

• SKU: 04L122157BT
• Mark: Audi
• Condition: Used
• OEM Part Number: 04L122157BT
• Substitutable numbers: 04L122157BT, 04L 122 157 BT
• Category: Coolant Hoses

Purpose and function in the cooling system

The coolant hose in Audi A4 B9 and Audi A5 F5 models with a 2.0 TDI engine is responsible for the controlled flow of coolant between the radiator and engine components. A properly selected and leak-free hose:

• maintains proper fluid circulation throughout the entire circuit,
• reduces the risk of localized overheating and cooling efficiency loss,
• ensures stable thermal conditions during city and highway driving.

Thanks to its design tailored to the specific 2.0 TDI configuration, the hose maintains the correct geometry, which facilitates installation and minimizes hose stress in the engine bay.

Construction and fitment for Audi A4 B9 / A5 F5

The offered coolant hose is an OEM Audi part, designed specifically for the engine bay architecture of the A4 B9 and A5 F5. This means:

• factory-matched connection diameters for radiator and engine ports,
• a properly shaped hose route that avoids critical auxiliary components,
• retention of the correct flexibility, allowing for the compensation of power unit vibrations.

This solution reduces the risk of leaks resulting from improper hose positioning and facilitates future maintenance.

Condition of the component and benefits of choosing a used OEM part

The hose comes from disassembly, which allows for combining an attractive cost with the preservation of the manufacturer's original specifications. Compared to low-quality aftermarket replacements, a used OEM component:

• maintains compliance with factory flow parameters,
• is made of materials selected for specific thermal and pressure loads,
• retains compatibility with factory clamps and mounts.

For Audi users who want to restore proper cooling system operation without excessive costs, this is a technically sound and economically beneficial solution.

Importance of a functional coolant hose for the 2.0 TDI engine

In diesel engines such as the 2.0 TDI, a stable operating temperature is crucial for the durability of the power unit, turbocharger, and auxiliary equipment. A leaking or degraded coolant hose can lead to:

• coolant loss and pressure drops in the system,
• an increase in engine operating temperature,
• accelerated wear of mechanical components.

Replacing the hose with a functional OEM component allows for the restoration of proper fluid circulation and reduces the risk of costly repairs associated with overheating.

More about diagnostics and cooling system operation

To better understand the symptoms of overheating and the impact of individual components on the durability of the power unit, it is worth reading the guide on the operation of the cooling system and radiators in various car models: Engine cooling system – overheating, repair, and used radiators. The article helps to assess when replacing a coolant hose is justified and how to approach comprehensive maintenance in this area.

If you are planning a comprehensive repair or upgrade of the cooling system area in your Audi and need other elements from the same group, such as additional pipes, return hoses, or sections connecting to the heater core, check the available parts in the Audi cooling system hoses and pipes category.