thunderstick

91 Z28 - gauge is reading "cold" when at normal operating temp, or so i suspect. i have a 180 t-stat and a 200/185 fan switch, stat opens up as advertised and if the fan comes on, it shuts back off as advertised. (i know this because of an indicator lite on my dash) on the gauge it is below the mark between 100 and 220. one would think that the mark between would be 160, and it reads below that. if i ground the wire out, it will peg the gauge past the 260 mark, but i would like to be able to check it for correct temp. gm states to use JXXX tool, with predetermined resistance, but i don't have the luxury of owning one of those tools, only a standard multi-meter. so, if someone can school me in the how-to to check the gauge, i'd appreciate it. thx.

CaliChevyLover

i put in an aftermarket temp gauge in my car

i hooked up a scan tool that can monitor engine temp, just sat there and the bitch idle til it got HOT.

when the scanner said around 194/195, checked the tstat hose, it started gettin hot.
then checked the gauge to see where the needle was at. fairly accurate.

did the same for when it hit about 235 when the fan comes on

deadbird

The gauge is most likely liner in its reading. Meaning, 100 is actually 180.
Mine sits on the quarter mark all day long (195°F thermostat, quater mark is 200°).

thunderstick

cool - thanks for the replies. been wanting to get a scan tool anyways, but with regard to the other post, the temp indicator read the same as yours when i ran a 195 in it, so most likely, all is well. makes sense. thx again, as always.