Temperature sending unit

[Jsooter]

I have the valve cover off to replace a leaking gasket and have decided to replace the temperature sending unit since it is not working 100% (I've bench-tested the temp/fuel gauges and they work great with a resistor).

Since the sending unit is grounded through the head, should I use teflon tape or thread seal...or nothing? Will tape or thread seal interfere with the ground?

I imagine that the threads would cut through the tape enough to supply a ground, especially if I only put tape on the top 1/3 of the threads.

Any words of advice?

Thanks!
Jerry

 

[Torxhead]

It is probably debatable but I would think you will make better electrical contact without the tape or any sealant. To make sure your head is grounded correctly you could run a #10 wire from someplace like the coil mount to the battery negative terminal. Cast iron is not a terrific conductor of electricity, spark plugs like a good ground also.

 

[DHugg]

I have the valve cover off to replace a leaking gasket and have decided to replace the temperature sending unit since it is not working 100% (I've bench-tested the temp/fuel gauges and they work great with a resistor).

Since the sending unit is grounded through the head, should I use teflon tape or thread seal...or nothing? Will tape or thread seal interfere with the ground?

I imagine that the threads would cut through the tape enough to supply a ground, especially if I only put tape on the top 1/3 of the threads.

Any words of advice?

Thanks!
Jerry

I use copper anti-seize on any threaded part that carries current. That includes plugs, grounding wire bolts, terminals on gage backs and the like. It serves a dual purpose: good current passage and won't lock up and require more muscle that is appropriate to remove.

 

[Jsooter]

I found an interesting page on a Corvette site. They took ohm readings with:

a) no tape
b) 3 turns of tape
c) 20 turns of tape

The difference between the three readings was minimal (less than 2 ohms at room temp).

Their conclusion was: "The chances of teflon tape affecting the gauge reading are remote - the pipe threads are very sharp, and cut through the tape with little effort"