Overview
The thermostat housing for the Mercedes-Benz W176 A-Class (A200) and W246 B-Class (B200) equipped with the M270 engine is a critical engine cooling component that helps regulate engine temperature by controlling coolant flow. This housing unit not only holds the thermostat in place but also integrates several coolant channels that direct engine coolant between the engine block, radiator, and heater core.
Compatibility
This specific thermostat housing is designed for:
- Mercedes-Benz A-Class W176 (2012–2018) – A200 with the M270 engine
- Mercedes-Benz B-Class W246 (2012–2018) – B200 with the M270 engine
Always verify the compatibility using your VIN (Vehicle Identification Number) or consult your mechanic to ensure proper fitment.
Function and Importance
The thermostat housing serves two main purposes:
- Holding the Thermostat: It securely contains the engine thermostat, which opens and closes based on engine temperature.
- Coolant Flow Management: It directs the coolant between the engine and the radiator. When the engine is cold, the thermostat remains closed to allow the engine to warm up. Once the optimal operating temperature is reached (typically around 90°C), the thermostat opens, allowing coolant to flow to the radiator and dissipate heat.
A faulty thermostat housing or thermostat can lead to overheating, engine performance issues, or increased emissions.
Construction and Features
- Material: Usually made of high-grade aluminum or reinforced composite plastic, depending on the OEM or aftermarket supplier.
- Integrated Sensor Port: Many variants include a port for a coolant temperature sensor.
- Sealed Design: Comes with integrated gaskets or O-rings to ensure leak-free operation.
- Thermostat Included (in most units): Many aftermarket and OEM kits include a pre-installed thermostat rated typically at 87°C or 90°C.
Common Symptoms of Failure
- Coolant leaks around the housing
- Engine overheating or not reaching operating temperature
- Erratic temperature gauge readings
- Check Engine Light (due to coolant temp sensor faults)
Replacement and Maintenance
Replacing the thermostat housing is a moderately difficult task, usually requiring removal of the intake manifold and draining of the cooling system. It is often replaced during coolant system overhauls or when upgrading or servicing the thermostat.
Conclusion
The thermostat housing for the M270 engine in the A200/B200 models plays a vital role in maintaining proper engine temperature. Ensuring this component is in good working condition is essential for engine longevity, fuel efficiency, and optimal vehicle performance.