How to test temp sensor

"Just wondering if there was a

"Just wondering if there was a easy way to test my engine water temp sensor on a 04 8.1. The gauge has power to it but has quit registering a reading, just put this new engine in, so this is the old sensor. Is there a way to test it? Thanks for any info. Joe"

"mmmm.... the sensor is the th

"mmmm.... the sensor is the thingy in the engine block. If you have a new engine, it should have a new sensor.
This system consists of three things... four if you count the connection to +12.. gauge, sensor and the wire inbetween.

If you disconnect the wire at the sensor (usually called temperature sender) on the engine and ground it momentarily, the gauge on the dashboard should peg to max reading.
If it doesn't, then the problem is between the wire in your hand and the gauge on the dash.
If it does, then the sender in the engine is bad (or a poor connection to the wire)... or, you have the temperature sensor wire connected to the temperature alarm switch which many new engines have."

"Thanks Robert, New engine lon

"Thanks Robert, New engine long block used my old stuff, there are two sensors 1 just below the thermostat the other on the metal pipe that runs between the to heads. Part #s 3850397 & 3852029 The grounding idea seems like a good plan I will give it a try. Thanks Joe"

"Thinking about it the sender

"Thinking about it the sender is below the thermostat and the sensor is on the pipe that runs between the heads, should I disconect the sensor to test the sender by grounding it?"