關鍵是“Begin with a cold engine. Remove the radiator cap and start the engine. Set your digital multimeter to DC volts at 20 volts or less. When the engine reaches operating temperature, insert the positive probe directly into the coolant”
目的是讓coolant循環到radiator才能量準，這隻有在coolant溫度達到一定程度thermostat打開了才能循環。不過發動機轉不轉我測量的結果幾乎沒有差別。
