57 Vette Needs help with temp sender

[Big D]

I have heard that I can run a resistor inline to get my gauge to read the correct temp, I am running 170-190 according to the infra red, but the gauge goes to 220 , I never can tell if I am overheating, any suggestions to what resistence I should start with?

 

[youwish2bme]

Sounds like you need to go to Auto Zone and get Wells TU5 temp sender... Dave..

 

[ptuner11]

if the wells tu5 doesn't work, it didn't for me, Central corvette sells a variable resistor... 20 bucks , i think.
use an infrared gun to make sure the gauge is accurate at high temp.

 

[JohnZ]

The Wells TU-5 is closer than most, but doesn't always work well - depends on the value of the shunt resistor that AC installed on the gauge when it was built (there were several, used to calibrate the gauge at assembly). You can install the CC variable resistor to make the gauge accurate at one known point and calibrate that point with an I.R. gun, but it will make the gauge less linear than it is already and readings above and below that point will be less accurate. Or, you can go to Radio Shack and get a 0-100 ohm variable potentiometer (a/k/a volume control) for $5.00 and make your own - you can leave it in the circuit, or use it to determine the exact resistance you need for your chosen calibration point, then make up a resistor pack (Radio Shack again) with the same value.