Mercedes W169 W245 OM640 Coolant Thermostat Housing Cooling Unit A6402000715

Mercedes W169 W245 OM640 Coolant Thermostat Housing Cooling Unit is a factory-made cooling system component designed for OM640 diesel engines used in compact Mercedes A-Class and B-Class models. This used housing ensures proper coolant flow and stable thermostat seating, which translates into correct operating temperature of the power unit. It is a practical solution for users looking for original geometry and fitment without the need to resort to aftermarket replacements of unknown origin.

Specifications and technical data

• SKU: A6402000715
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6402000715
• Substitutable numbers: A6402000715, A 640 200 07 15
• Fuel type: Diesel
• Category: Thermostats & Housings

Purpose and function in the cooling system

The thermostat housing in the OM640 diesel engine is responsible for the precise routing of the coolant flow between the engine block, the radiator, and other system components. The proper design of the housing allows for:

• maintaining a stable operating temperature of the power unit,
• reducing the risk of engine overheating or undercooling,
• proper cooperation with the thermostat and temperature sensors,
• a tight connection with cooling system hoses.

By maintaining the original architecture of the flow channels, the housing supports even cooling of the diesel engine, which is important for both the durability of the unit and fuel economy.

Benefits of using an original thermostat housing

For components such as the thermostat housing, precise fitment to the specific engine and body is crucial. Using an original solution for the Mercedes W169 and W245 ensures:

• compliance with the factory cooling system design,
• correct positioning of ports and mounting points,
• easier installation without the need for modifications,
• consistency with other system components, such as hoses and the radiator.

This is particularly important in diesel engines, where stable operating temperature affects engine refinement, exhaust emissions, and the durability of auxiliary equipment.

Installation and operational characteristics

The thermostat housing from this series has been designed for the compact engine bay layout in W169 and W245 models. The design provides:

• dedicated mounting points for the OM640 unit,
• a port layout adapted to factory coolant hoses,
• geometry ensuring proper installation of the thermostat inside the housing.

When correctly matched to the specific engine version, installation proceeds in an orderly manner, and the cooling system connections maintain the required tightness. The used component allows for an economical repair while maintaining original Mercedes specifications.

Application in OM640 diesel engines

Diesel engines require a precisely operating cooling system because they work under higher thermal loads than gasoline units. The thermostat housing dedicated to the OM640 diesel supports:

• efficient engine warm-up after start-up,
• maintaining optimal temperature across a wide range of loads,
• stable cooperation with the cabin heating system.

Selecting the right housing for a specific diesel engine is essential for maintaining trouble-free operation of the cooling system and reducing the risk of leaks or improper fluid circulation.

Expanding the cooling system in a Mercedes

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 additional housings, bodies, or components working with the thermostat, check out the available parts in the Mercedes Thermostats and Housings category.

For drivers who are simultaneously servicing other vehicle systems, practical tips on the safe selection of used components may also be useful – especially in areas critical to safety. In such a case, it is worth reading the guide Second-hand braking system: how to safely choose discs, calipers, and ABS?, which shows what to look for when buying used parts in a specialized store.