A properly functioning thermostat regulates engine temperature, allowing the ECU to maximize fuel economy and performance, while minimizing tailpipe emissions. It also ensures that the air coming out of your vents in the winter gets hot enough to keep you comfortable.
Unlike conventional thermostats, this particular unit from OEM supplier Behr includes the thermostat housing, and housing-to-engine o-ring.
When replacing the thermostat, it is strongly recommended that you purchase the 20x3mm seal that connects the coolant pipe to the thermostat housing. Make sure you choose to add one from the drop down below when adding this thermostat to your cart. The two M7x28mm thermostat housing mounting bolts are an option, but not considered to be a must.
Also, during replacement, you will lose a considerable amount of coolant, so while the system is evacuated you may want to replace the coolant flange, both grey top coolant sensors, and of course, the coolant.