Temp gauge irregularities

[Hoeyboy]

...'92 GMC Suburban K2500, 5.7 ltr...when I originally purchased it, the factory gauge pod coolant temperature did not move. The gauge sweeps full right when I start the vehicle, but then did not move as the vehicle warmed. The truck has always had great heat.

Changed the temp sender located on the driver's side head. While I was at it, I changed the thermostat as well, going with a factory 195°. Voila, the gauge moved. It moved however, only to about 110° on the gauge.

Found out last week that on this truck there is also a second temp sender, located near the thermostat housing. I changed that out as well. Still, the gauge reads no higher than around 110°.

I'm not worried about the truck running warmer or colder. It just chaps me...

 

Gauge error? Ideas?

[thx1138v2]

The second one you found goes to the ECM and has no effect on the gauge. Those senders that are in the head are hard to figure. I went through 5 of them before it got even close. Many of them say "100% OEM compatible" but as far as I can tell that's only the physical configuration, i.e. threads and electrical clip but not the electrical part. The sensor works on a  logarithmic scale. I took the one that was close and adjusted the needle on the gauge to where it was near correct at the operating temperature. It reads high when the engine is cold but since I'm concerned with the operating temperature that's OK with me. I want to know when it is over temperature. I figured that was as close as I would get.

 

BTW, that was on a '94 C1500 4.3L

[LDM]

The gauges on these seem to be hit or miss on working properly.  My brother's 97 the temp gauge never goes past the 1/4 mark.  But I can hook my diagnostics/data logger up and read the temp from the PCM, it is always correct.  You used to be able to get the air core parts to rebuild them off Ebay but they seem to be getting harder to find anymore.  A lot more expensive as well.