My old 2000 Tahoe Limited (5.7) always ran with temp gauge only 1/4 of the way. By the gauge it was too low. Since I always had good heat I never worried about it. Although the last thin an Auto Technician never want to work on their own stuff.

 

Yes there are 2 senders and I replaced the one for the gauge when I replaced the thermostat. This is a new problem to this truck up until a few months ago the gauge read 195 degrees or just under the 210 mark, I have not check the temp of the heat at the vents but it had plenty of heat back during the winter. I will get a temp reading at the thermostat, I would think the housing temp would be pretty close to the water temp.

 

Just so we're on the same page, you replaced the sensor that takes one wire (for the gauge)? The ECT sensor for the PCM, on the other hand, takes two wires one of which is the ground reference (can't trust the ground provided by the water jacket for the precision it requires).

 

That is correct, it is located on the side of the head. Driver side between cylinders 1 and 3.

 

Check your water temp. If it is in fact running cold and you're sure the thermostat is good, replace the intake gaskets.

If the restrictors are blown, it never will come up to temp.

Allan

 

this one isnt for the PCM, it is for the intrument panel.

 

The DK GRN wire from the sensor (sender) ends up on pin 13 on the electrical connector at the I/P cluster (had to look it up). The movement of the gauge needle reflects the resistance change across the pin 13 and ground. Try unplugging the electrical connector from the sensor with key on, engine off after it's warmed up. The needle will drop with the resistance going to infinity. Thus, anything that affects the resistance measurement (resistance on the wire between the two end points, difference between the ground reference between the engine block and chassis grounding point for the I/P cluster, reference voltage which is the charging system voltage with engine running) will affect the position of the needle. What I'm getting at is, don't assume a huge mechanical problem.

 

Put gauge in head and to temp

 

These clusters were also known for not reading properly, so what you see may not be what the actual temp is. There are 2 sensors, one for the gauge and one for the computer. You should check to be sure the connectors are not corroded(also a common problem)

As it has been pointed out, a thermometer in the radiator is not accurate at all.....That temp will never be as high as the internal engine reading.

You do need to use a scanner to verify the gauge reading, which is the temp the computer sees. The truck should run consistently between 190 and 214.

 

Dude, quit making empty posts. It's obvious what you're doing, flashing the ad in your signature.