Acura 37870-PJ7-003 Water Temperature (Tw5) Sensor Assembly

The coolant temperature indicator system consists of a temperature gauge mounted in the instrument panel and a coolant temperature sending unit mounted on the engine directly below the distributor. The coolant temperature sending unit is located near the distributor and is the one with the single wire. If an overheating indication occurs even when the engine is cold, check the wiring between the dash and the sending unit for a short circuit to ground. If the gauge is inoperative, test the circuit by briefly grounding the wire to the sending unit while the ignition is on, but ensure the engine is not running for safety. If the gauge deflects full scale, replace the sending unit. If the sending unit is suspect, check the resistance of the sensor with the engine cold and hot. The resistance should decrease as the temperature increases. When the engine is cool, 130-degrees or cooler, the resistance should be approximately 140 ohms; when the engine is at normal operating temperature, 186-degrees or warmer, the resistance should be approximately 30 to 46 ohms. If the sending unit must be replaced, simply unscrew it from the engine and quickly install the replacement. Use sealant on the threads.

It is important to handle the coolant sensor with care because damage to the sensor will affect the fuel injection system's operation.