Mercedes X166 W222 Cooling Engine Water Coolant Hose Pipe M157 M278 A2782031417

Mercedes X166 W222 Engine Coolant Hose M157 M278 is an original cooling system component from the Hoses, Pipes and Tubes group, designed for M157 and M278 engines. Thanks to its factory design, Mercedes ensures proper coolant flow, stable engine thermal operation, and compliance with the design requirements of X166 and W222 models. This solution is dedicated to users who expect precise fitment and preservation of the cooling system's factory operating parameters.

Specifications and technical data

• SKU: A2782031417
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2782031417
• Substitutable numbers: A2782031417, A 278 203 14 17, A 157 016 00 00, A1570160000
• Part type: Hose
• Category: Hoses, Lines & Pipes

Purpose and Function in the Cooling System

The engine coolant hose in Mercedes X166 and W222 models with M157 and M278 engines is responsible for the controlled flow of coolant between key system components. A correctly selected element of this type:

• maintains stable engine operating temperature across a wide range of loads,
• ensures leak-proof connections within the cooling system,
• minimizes the risk of engine overheating,
• maintains compliance with the factory hose routing geometry.

Thanks to its design consistent with the manufacturer's project, the hose works with original connectors, clamps, and other cooling system elements, which facilitates installation and reduces the risk of material stress.

Benefits of Using an Original Mercedes Hose

Using an original coolant hose in M157 and M278 engines brings a number of practical operational benefits. The most important include:

• Factory Fitment – maintaining the correct length, diameter, and shape of the hose, which translates to proper placement in the engine bay.
• Cooling System Compatibility – the hose works with the stock fluid pump, radiator, and other components without requiring modifications.
• Stable Thermal Operation – proper coolant flow promotes uniform heat dissipation from the engine.
• Reduced risk of leaks – a correctly selected element reduces stress on connections and fittings.

This solution is particularly recommended for servicing high-performance engines where the cooling system operates under increased thermal and hydraulic load.

Condition, Verification, and Service Application

The offered coolant hose comes from the group of used parts, allowing for economical repair while maintaining the original manufacturer's specifications. This type of element is a good choice in situations where:

• a quick replacement of a damaged or leaking hose is necessary,
• you want to maintain the factory cooling system routing,
• you want to avoid problems with fitting aftermarket alternatives of uncertain geometry.

Before installation, a standard visual inspection and checking the condition of the connection surfaces are recommended to ensure leak-proof connections after installation in the vehicle.

Practical Workshop Application and Parts Selection

In professional Mercedes vehicle service, the engine coolant hose for X166 and W222 models with M157/M278 engines is treated as an essential component of cooling system maintenance. When selecting parts, it is worth paying attention to:

• compatibility with the specific engine type (M157 or M278),
• designation for the correct body generation,
• consistency with other cooling system components used in the vehicle.

This minimizes the risk of installation problems and ensures correct system operation over a long service life.

If you are planning a comprehensive repair or upgrade of the engine area in your Mercedes and need other elements from the same group, such as fluid lines, return hoses, or connecting pipes, check the available parts in the Mercedes Hoses, Pipes and Tubes category.