Temp Gauge reading

[Spector]

Is there a quick way to tell if the reason for my temp gauge not moving beyond the bottom line (used to read in the middle) is due to a themostat, a bad gauge or a bad sensor/sending unit??? As the engine heats up and seems to operate fine I don't think it is the thermostat but could be.

Any quick way to make a determination.

 

[Chris142]

An infrared gun pointed at the T-Stat housing willtell you the actual engine temp.

 

[The_Jeff]

If it's a single wire sending unit, turn the key on, engine off, and ground the wire. Gauge should be all the way one way with it ungrounded (usually cold) and all the way the other way with it grounded (usually hot.)

Two-wire sending units substitute a paper clip across the terminals.

This can create a code if that sender is also used for the ECM and not just the gauge.