Audi S5 8T Secondary Air Injection Pipe Hose Line 4.2 FSI CAUA 8T0133817B

Audi S5 8T Secondary Air Injection Pipe Hose Line 4.2 FSI CAUA is an original crankcase ventilation system component designed for the 4.2 FSI petrol engine. Thanks to its factory geometry and precise fit for the CAUA engine, it ensures stable flow of air and crankcase gases, which promotes smooth engine operation and proper interaction with the secondary air system.

Specifications and technical data

• SKU: 8T0133817B
• Mark: Audi
• Condition: Used
• OEM Part Number: 8T0133817B
• Substitutable numbers: 8T0133817B, 8T0 133 817 B
• Fuel type: Petrol
• Category: Secondary Air & Smog Pumps

Purpose and function in the secondary air system

The breather hose in the Audi S5 8T with the 4.2 FSI CAUA engine operates within the secondary air system, responsible for the controlled discharge of oil vapors and gases from the crankcase into the intake system. A properly selected air pipe reduces the risk of leaks, incorrect air-fuel mixture composition, and diagnostic errors related to exhaust emissions in the petrol engine.

This component is particularly important in high-power units such as the 4.2 FSI, where stable crankcase pressure and proper operation of the secondary air system affect engine refinement, performance, and durability.

Design, fitment, and installation

The hose was designed by the Audi brand as part of the secondary air system, taking into account the specific routing in the engine bay of the S5 8T model. The properly shaped air pipe ensures:

• precise fit to the mounting points in the engine bay,
• stable connection with the breather and intake system components,
• resistance to typical thermal and pressure loads in a petrol engine.

Thanks to its factory design, installation is predictable – the hose follows the original routing, which facilitates service and reduces the risk of interference with other components.

Characteristics of the used component

The offered hose belongs to the group of original used parts, meaning it comes from dismantling and retains the manufacturer's factory specifications. This type of component is a good choice for servicing the breather system in daily-driven vehicles, where the priority is to maintain the original design at reasonable repair costs.

Choosing a used part allows you to maintain the integrity of the entire secondary air system while providing an economical alternative to purchasing a new component, especially in the case of specialized hoses dedicated to specific engine versions.

Benefits of using an original breather hose

Using a breather hose dedicated to the Audi S5 8T with the 4.2 FSI CAUA petrol engine offers a number of practical benefits:

• maintaining factory engine performance characteristics due to proper routing of crankcase gases,
• reducing the risk of oil leaks and blow-by that can affect intake system operation,
• better cooperation with the secondary air system responsible for emission reduction,
• easier diagnostics – the original component is correctly recognized in service documentation and parts catalogs.

This solution is especially recommended when replacing damaged, perished, or leaking hoses that may cause unstable idle speed, increased fuel consumption, or engine control unit errors.

Technical support and related components

When performing service work on petrol units, it is also worth ensuring proper maintenance of the fuel supply system. Detailed information on diagnostics, selection by part numbers, and maintenance of components such as injectors, pumps, or the fuel tank can be found in the article: Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration.

If you want to make better use of the potential of dismantled parts and consciously choose components for your car, the following guide will be helpful: Used parts – your guide to the best offers in the automotive store, which discusses the principles of safe purchasing and operation of used components.

If you are planning a comprehensive repair or upgrade of the engine area in your Audi and need other elements from the same group, such as hoses, connectors, or exhaust system components, check the available parts in the category Audi secondary air pumps.