the nominal value is 300-360 ohms at 175-184 degrees farenheit. BUT, there are three coolant sensors. 1 for the computer, 1 for the temp guage, and 1 to activate the radiator fan. which one is it that u are interested in?Anyone know the resistance of the M42 coolant sensor when hot? Have seen 200, 350 and 400 ohms mentioned - I want to bypass the sensor with a resistor for a while - what's the best figure? Does it matter much?