To test the temperature sender, it is necessary to submerge its end in cold or hot water and measure the resistance. The first thing to do is to remove the single wire harness connector of the sender, ground the connector to the engine block to ensure that the gauge indicates full HOT. In case the gauge is working, proceed with the testing, and in case not, examine the wire harness between the sender and the gauge. The next step is to take off the coolant temperature sender of the engine and put it in water. Connect an ohmmeter to the sender connector and body, warm the water to the specified temperature, and measure the meter: in 1990-92 626 and MX-6 models, the ohm meter value should be 49-58 ohms at 176°F (80°C) and in 1995-98 Protege models, 153 ohms at 129°F (54°C) and in all other models, 190-259 ohms at 122°F (50 In case the reading falls beyond these specifications, change the sender. To remove and install, drain and recycle the engine coolant, disconnect the wire harness connector on the sender and take it out by turning it counterclockwise. Installation During installation, step three threads up the sender and apply sealant at the head starting with the third thread, but tighten to 57-82 inch lbs. (6.4-9.3 Nm).