Mercedes W168 M166 Thermostat Coolant Housing A1662030275

Mercedes W168 M166 Thermostat Coolant Housing is a component from the Thermostats and housings group, designed for the cooling system of the M166 engine in the W168 A-Class model. A properly selected housing ensures stable coolant flow and correct cooperation with the thermostat, which translates into safe engine operating conditions.

Specifications and technical data

• SKU: A1662030275
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1662030275
• Substitutable numbers: A1662030275, A 166 203 02 75
• Category: Thermostats & Housings

Purpose and function in the cooling system

The thermostat housing in the M166 engine is responsible for the precise seating of the component that regulates the engine's operating temperature. A correctly selected housing:

• stabilizes the position of the thermostat relative to the cooling channels,
• ensures a tight connection with the cooling system hoses,
• enables proper direction of fluid flow during the warm-up phase and normal engine operation.

Thanks to this, the cooling system maintains an optimal temperature range, which promotes the durability of components and the proper operation of the M166 unit in the W168 body.

Technical characteristics and fitment

The housing has been designed specifically for use in the M166 engine, which means a construction consistent with factory mounting points and cooling channel geometry. Precise fitment to the cooling system reduces the risk of leaks, facilitates installation, and allows for maintaining the original operating characteristics of the thermostat.

The component comes from the Mercedes brand, which in practice means maintaining the vehicle manufacturer's quality standards regarding material, casting, and the finish of surfaces that interact with seals.

Condition, verification, and service application

The presented Mercedes W168 M166 Thermostat Coolant Housing is a used part, sourced from dismantling. This type of component is particularly useful in:

• cooling system repairs after a thermostat failure or engine overheating,
• preventive maintenance when corrosion or damage to the housing has been identified,
• restoring the original cooling system configuration after previous modifications.

Choosing an original housing from dismantling allows for maintaining the factory geometry of the coolant flow, which is essential for the stable operation of the power unit in the long term.

Benefits of using an original thermostat housing

Using a component from the Thermostats and housings group sourced from the vehicle manufacturer brings a number of practical service benefits:

• maintaining factory fitment to the cylinder head and cooling hoses,
• reducing the risk of issues with system bleeding after installation,
• the ability to use standard gaskets and mounting elements.

For workshops and users, this means efficient installation, predictable cooling system behavior, and easier diagnostics of potential future faults.

Expanding Mercedes cooling system service

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 thermostat bodies, covers, or additional mounting elements, check the available parts in the Mercedes Thermostats and housings category.

If you are interested in a broader approach to servicing premium cars using proven components from dismantling, it is worth checking out the guide: Luxury within reach – how to service a Porsche legend using proven used parts. You will find practical tips there that can also be applied to servicing Mercedes vehicles.