Mercedes W203 W211 M112 Exhaust Manifold Cylinder 1-3 Petrol A1121403009

The Mercedes W211 M112 exhaust manifold 1-3 petrol is a factory exhaust system component designed for M112 series petrol engines in the W211 E-Class model. This used front-of-vehicle manifold ensures correct exhaust gas flow, stable engine operation, and proper conditions for further exhaust system modifications. Thanks to its design consistent with manufacturer solutions, it is a safe choice for repairing or reconstructing the exhaust system in Mercedes cars.

Specifications and technical data

• SKU: A1121403009
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1121403009
• Substitutable numbers: A1121403009, A 112 140 30 09, BG
• Location on the vehicle: Front
• Fuel type: Petrol
• Category: Manifolds & Headers

Purpose and Fitment for Mercedes W211 M112

The presented exhaust manifold belongs to the exhaust manifolds category and has been designed for M112 petrol engines in the W211 body style. Its placement at the front of the vehicle allows for direct connection to the engine head and the subsequent section of the exhaust system, facilitating service and diagnostics. The manifold's design is optimized for exhaust gas flow for petrol units, contributing to stable engine operation across the full load range.

Technical and Functional Characteristics

The exhaust manifold is responsible for collecting exhaust gases from cylinders 1–3 and directing them to the rest of the system. In practice, this translates to:

• maintaining appropriate back pressure in the exhaust system,
• compatibility with the factory M112 engine control,
• minimizing leaks in the critical area near the cylinder head,
• stable operating conditions for lambda sensors and other system components.

By maintaining the original channel geometry, the manifold supports correct cylinder filling and smooth engine operation, which is particularly important for petrol engines used in both city and highway driving.

Application in Petrol Systems and Installation Aspects

The component has been prepared to work with the petrol engine exhaust system, meaning appropriately selected channel diameters, mounting point locations, and a shape tailored to the W211 engine bay. Its front-of-vehicle placement requires precise fitting with the cylinder head and the subsequent exhaust section, therefore using a manifold consistent with the factory solution minimizes the risk of installation problems.

When replacing, it is recommended to:

• check the flatness of the mating surface with the cylinder head,
• use new gaskets and fasteners,
• inspect the condition of other exhaust system components at the front of the vehicle.

Condition, Origin, and Benefits of Choosing a Used Manifold

The offered exhaust manifold is a used part, sourced from a dismantled Mercedes vehicle. Choosing this solution allows for maintaining the factory exhaust system performance characteristics while optimizing repair costs. A used OEM part is a sensible option when compatibility with the M112 unit and maintaining original exhaust gas flow geometry are priorities.

Mercedes Exhaust Manifolds – Further Selection Options

If you are looking for other Mercedes exhaust manifolds for different engine versions or body styles, check out our dedicated category Mercedes exhaust manifolds, where you will find a wide selection of exhaust system components for this brand.

More About Used Manifolds and Exhaust Systems

Are you planning an upgrade or a more extensive repair of your car's exhaust system and want to better understand the differences between stock and performance solutions? See our practical guide on our blog: Performance Exhaust Systems: Used Manifolds and Sport Catalytic Converters on the Road, where we discuss selecting used manifolds for popular brands, including Mercedes.