Audi A4 S4 B8 A5 8T Turbocharger Oil Return Pressure Line 2.0 TDI 03L145736AA

Audi A4 S4 B8 A5 8T Turbocharger Oil Return Pressure Line is an original component from the Turbochargers and parts group, designed for the precise delivery of oil to the forced induction system in 2.0 TDI diesel engines. A properly selected oil line ensures stable lubrication of the turbocharger, which translates into its longevity and the safe operation of the entire powertrain.

Specifications and technical data

• SKU: 03L145736AA-1
• Mark: Audi
• Condition: Used
• OEM Part Number: 03L145736AA
• Substitutable numbers: 03L145736AA, 03L 145 736 AA
• Part type: Turbocharger Hose
• Category: Turbos & Parts

Purpose and function of the turbocharger oil line

The turbocharger oil line in Audi A4, S4 B8, and A5 8T models with a 2.0 TDI engine is responsible for the controlled supply of engine oil to the turbine bearings. Stable pressure and proper oil flow reduce the risk of rotor overheating, minimize bearing wear, and help maintain correct boost characteristics across the entire RPM range. Using an original line from the Turbochargers and parts group allows you to maintain the factory operating parameters of the system, which is particularly important in diesel units where the turbocharger operates under high thermal and mechanical loads.

Benefits of using an original Audi component

The original turbocharger oil line for Audi has been designed for the specific geometry of the 2.0 TDI engine and the layout of accessories in the engine bay. As a result, it provides:

• precise fitment to mounting points and oil ports,
• proper routing of the line without the risk of rubbing against other components,
• preservation of factory oil flow cross-sections,
• compatibility with the original turbocharger used in the Audi A4, S4 B8, and A5 8T. Choosing an original Audi component reduces the risk of leaks, oil pressure drops, and improper turbine lubrication, which in the long run can protect against costly regeneration or replacement of the entire turbocharger.

Installation and operational characteristics

The turbocharger oil line for the Audi A4 S4 B8 and A5 8T is structurally prepared for installation in place of the factory component, without the need for system modifications. Properly selected ends and the shape of the line facilitate the mechanic's work and allow for the maintenance of the correct oil routing path. In practice, this means:

• consistency with factory connection points on the engine block and turbocharger,
• maintaining required distances from hot components (manifold, turbine housing),
• reduction of mechanical stress at connection points,
• the ability to use standard Audi service procedures. For the user, this translates into predictable installation time and a lower risk of operational problems associated with incorrect line positioning.

The importance of selecting the right oil line

In 2.0 TDI engines used in the Audi A4, S4 B8, and A5 8T, the turbocharger is one of the key elements affecting driving dynamics and combustion efficiency. A properly selected oil line has a direct impact on:

• stability of oil pressure in the forced induction system,
• heat dissipation from the turbine bearings,
• reducing the risk of rotor seizure,
• maintaining factory power and torque parameters. Using a line with an incorrect diameter, length, or geometry can lead to local overheating, a drop in turbine efficiency, and in extreme cases, its damage. Therefore, choosing an original Audi component is a safe and technically justified solution.

Product condition and informed choice of used parts

The offered turbocharger oil line is a used component, which in the case of original Audi parts represents an attractive alternative to replacements of unknown origin. A used OEM component retains factory geometry and quality standards, while simultaneously allowing you to optimize the cost of repairing the forced induction system. If you want to better understand why the market is increasingly choosing used OEM components for premium brands, it is worth reading the article: Crisis in the new parts market? Why used originals for premium cars are the hottest trend in 2026. You will find practical arguments there in favor of making an informed choice of proven second-hand components. If you are planning a comprehensive repair or upgrade of the forced induction area in your Audi and need other elements from the same group, such as oil lines, return lines, or small mounting accessories, check out the available parts in the Audi Turbochargers and parts category.