BMW’s M54 engine was a solid step forward in the development of power, efficiency, and lower emissions, but that lower emissions came at a price. The factory thermostat is electronically controlled to keep the engine running between 80-103°C, whereas we like to maintain 80°C or less for maximum power. Additionally, the mechanical failsafe doesn’t open up until the coolant temperature reaches 110°C, or 230°F, which is about the point when we turn our race cars off and park them – it’s no wonder so many M54 engines get overheated and killed!
The AAF E46 M54 Low Temp Thermostat Kit is designed to give the control of proper engine operating temperature back to the owner/builder by replacing the stock electronic thermostat with a manual unit. This allows the engine to run at the proper, and much safer, operating temperature, improving engine longevity, reduces stress from high-temp. operation, reduces heat soak, and increases power!