Exhaust Manifold Mercedes W211 W163 M112 Petrol Left N/S A1121403109 4-6 Cyl

Mercedes W211 W163 M112 Gasoline Exhaust Manifold A1121403109 is an original part from the Exhaust Manifolds group, designed for M112 gasoline engines and installed on the left side of the engine. The used manifold ensures factory exhaust channel geometry, which promotes stable engine operation and proper exhaust gas evacuation in Mercedes mid-size and SUV vehicles.

Specifications and technical data

• SKU: A1121403109-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1121403109
• Substitutable numbers: A1121403109, A 112 140 31 09, KD
• Location on the vehicle: Left
• Fuel type: Petrol
• Category: Manifolds & Headers

Purpose and Fitment for M112 Unit

The presented exhaust manifold has been specifically designed for M112 gasoline engines used in Mercedes W211 and W163 models. The construction, adapted to the specific mounting side in the engine bay, allows for correct exhaust routing, proper mounting point positioning, and compatibility with the factory exhaust system.

By adhering to the original manufacturer's specifications, the manifold works with standard cylinder heads, accessories, and the rest of the exhaust system, which minimizes the risk of leaks and undue stress on adjacent components.

Exhaust Manifold Construction and Function

In a gasoline engine, the exhaust manifold plays a crucial role in collecting exhaust gases from individual cylinders and directing them to further system components, such as connecting pipes or the catalytic converter. For the M112 unit, maintaining the correct length and cross-section of the channels is important to avoid disrupting exhaust flow and generating excessive backpressure.

The original manifold design ensures:

• stable exhaust gas evacuation from the left cylinder head,
• correct positioning relative to the block and accessories,
• maintenance of the engine's factory operating parameters.

Benefits of Using an Original Used Manifold

Choosing a used OEM exhaust manifold for a Mercedes allows for structural consistency of the powertrain without the need for aftermarket replacements with uncertain geometry. Factory fitment reduces the risk of installation problems, leaks at the head interface, and incorrect alignment of further exhaust components.

A used part with preserved material structure is also a cost-effective solution for exhaust system repairs, especially for vehicles used intensively or in harsher thermal conditions.

Application in Service Practice

The Mercedes W211 W163 M112 Gasoline Exhaust Manifold A1121403109 is suitable for both standard replacement of a damaged manifold (e.g., cracks, leaks) and for comprehensive rebuilding of the exhaust system on the left side. Using an original part simplifies the mechanic's work, as the mounting points, shape, and channel routing are consistent with factory service documentation.

If you are planning a comprehensive repair or upgrade of the exhaust system area in your Mercedes and need other parts from the same group, such as manifolds for the opposite side, connecting sections, or additional mounting components, check the available parts in the Mercedes Exhaust Manifolds category.

More Information and Part Selection

To better understand the manifold's impact on gasoline engine operation and the possibilities of using used parts in exhaust systems, it is worth reading the guide on our blog: Performance Exhaust Systems: Used Manifolds and Sport Catalytic Converters on the Road.

If you want to check part compatibility with your car step-by-step based on the OEM number or vehicle data, the practical guide will also be helpful: Guide: How to Select the Right Car Part by VIN and OEM Number.