Automotive thermostats have grown far more sophisticated and complex over the years but the basic operating principle remains the same. At the heart of the thermostat is a cylinder with a small plunger. The cylinder is filled with wax and as engine coolant warms up during engine operation, the wax melts, expanding in the cylinder, moving the plunger and opening the thermostat to allow coolant flow to the radiator. The wax can be compounded to melt at different temperatures, allowing manufacturers like MAHLE to design thermostats with specific opening temperatures.
In the last decade, car manufacturers have improved engine emissions by increasing the engine operation temperature. 230 F is not uncommon on late model engines; however, there are times during vehicle operation when that high an opening temperature on a thermostat could be detrimental to engine life. Enter the electric thermostat. By embedding a small electric resistor within the wax element, we can, with a signal from the engine management system, heat the wax quicker than the coolant could, causing the thermostat to open sooner. Sometimes referred to as a map thermostat, (we map the thermostat opening parameters to signals from the engine management computer), these units do fail and require replacement. When replaced, it is important that the new unit be identical in design and function to the OE part.
MAHLE manufactures original equipment thermostats including these late-model electric designs. MAHLE Aftermarket supplies these to the service and repair industry in the MAHLE Original and BEHR brands. With our experience and capability, you can count on the replacement thermostats being perfect in every respect!
For application information and/or tech help, visit mahle-aftermarket.com