Average Operating Temperature...

I seem to remember my 1500 averaging out at about the 210 mark on the temp guage during operation. It seems after I swapped out my ECT sensor that the temp guage teeters between 210 and the mark that 3/4 position (260 I think).

Anybody know what temp it should operate at?

The 3 that I've had all ran around 205 to 210. Pretty much never changed.

I was reading in my Haynes Manual. Turns out that thereare two components in the Coolant Temp business. The Coolant TempSwitch and the Coolant Temp Sensor. I have replaced the Coolant Temperature Switch already.

Would the Coolant Temp Sensor cause the Guage to read high?

COuld the thermostat be defective by opening at a higher temp than normal?

I think when a coolant temp sensor goes bad, it usually takes a lot longer for the computer to know the engine is warm and it dumps more fuel then needed, thinking it's still cold. If you lost any antifreeze changing your switch, I'd make sure the aren't any air bubbles in your system, changing the thermostat is a good idea any time it comes up, as they are cheap and easy to fix. Where was the sensor you changed located and what year/engine is your rig?

I have a 95 K1500. I changed the Coolant Temp Switch. It's located between valve 1 and 3 on the drivers side of the engine block. My truck sat for about 6 months. I've flushed the coolant system 2 times in the last month to get it good and clean. I ran the engine with the radiator cap off for a few minutes and then I squeezed the top and bottom hoses to try to get all the air out. I also stood there for about 15 minutes adding 50/50 mix to the radiator to make sure it's full.

It's wierd that the temp goes up to 260 but then back down. It doesn't go all the way to red. I dunno

Spiking temperature is usually a sign of an air pocket. I usually get rid of them by running the truck until it's at operating temperature (when the thermostat opens) and then opening the radiator cap to the first notch and it'll usually slowly blow out some steam and maybe a little water, after it's done bubbling then open the cap the rest of the way and fill the radiator. Of course, be careful, since the steam will be hot. The other problems I've ran into that have volatile temperature are a bad water pump (the temp will climb at idle, then go down as you accelerate and the water pump speeds up) or a head gasket/head problem (which is leaking compression into the water jacket and making air bubbles). I looked at my '89 this morning and the temp sensor is right next to the thermostat housing, which would put it in the most likely place for an air pocket to form. I'm guessing your '95 is the same, if it is, maybe you should remove the sensor when it's completely cold and see if water leaks out or if it's not quite up to the sensor level.

Removed the sensor with engine cold. Coolant leaked out when I removed it. I familiarized myself with the Temp gauge today. When I drive my truck at no time does it go all th way to 260 (overheated). It hangs out at 210 and periodically goes to the 3/4 hash mark. Sorry for any misinformation.

Is there a problem?

Spiking temperature is usually a sign of an air pocket. I usually get rid of them by running the truck until it's at operating temperature (when the thermostat opens) and then opening the radiator cap to the first notch and it'll usually slowly blow out some steam and maybe a little water, after it's done bubbling then open the cap the rest of the way and fill the radiator. Of course, be careful, since the steam will be hot.

I looked at my '89 this morning and the temp sensor is right next to the thermostat housing, which would put it in the most likely place for an air pocket to form. I'm guessing your '95 is the same, if it is, maybe you should remove the sensor when it's completely cold and see if water leaks out or if it's not quite up to the sensor level.
A "spill-free funnel" is a much faster and safer way to insure the cooling system is full. They have an adapter that goes on in place of the radiator cap and the funnel goes into that.

The sensor on/near the thermostat housing is only for the computer, the one he replaced is the guage sender.

1/2 to 3/4 seems to be normal on GM trucks, many other users have had this "problem" that nothing fixed, my '86 fluctuates a lot too. As long as it stays out of the red, it's OK.