Mechanical Temperature Sensor?
 

I installed this sensor because my warning light is inoperable. Do not like not knowing what the temperature is. Question is I have a leak at the sensor T connection. Can you use Teflon tape on the threads of the sensor ?

Re: Mechanical Temperature Sensor?
 

I have a mech temp gauge on both my trucks, a 292 L6 and a 350 V8. In both cases the probe is mounted directly in the head.
While teflon tape might make extraction of the probe easier, I think isolating it from direct contact with the metal of the head could result in a lower, innaccurate reading. While there's no electric current to worry about, if it were electric, that would also block continuity.
I'm also not sure of your T configuration. Would there be any temperature difference between indications at the water pump, as opposed to the head? IDK. But the head is the preferred source.
All of this is my own, unprofessional opinion.
But maybe this discussion will be interesting to an ''expert.''

Re: Mechanical Temperature Sensor?
 

Teflon tape will not affect the temperature reading, but yours is not the ideal location if you want an accurate temperature. If you're going to use Teflon tape, I recommend the yellow; it's chemical resistant.

Re: Mechanical Temperature Sensor?
 

I spoke with my local engine shop who has built SBC engines for decades. I asked him about installing the sensor in the plugged passenger side head. It has a hex plug in it now. He suggested using the looped heater hose I have since the heater core has a leak. I ran the engine for about 15 minutes and the gauge was steady at 190 while idling. I wanted to keep the original waning light sensor as a visual indicator along with the mechanical gauge. Appreciate your input..Jack