2003 5.3 overheating problems

[briand069]

Do you have any other signs the truck is overheating? Just becasue the gauge reads high doesn't mean its overheating. Past experience for me is the sensors go bad first and to replace them if you don't have another way to test the temperature. I think this truck only has the one CTS for the gauge and the PCM but I will look later. If you have a good scan tool to hook up you could see if the PCM reads the same temp. Just my 2 cents.
Also, here's what should happen if it is overheating.
Engine Coolant Indicators

ENGINE COOLANT HOT
The IPC displays ENGINE COOLANT HOT message when the IPC determines that the coolant temperature is greater then 121°C (249.8°F) . The IPC receives a class 2 message from the PCM indicating the coolant temperature.

ENGINE OVERHEATED
The IPC displays ENGINE OVERHEATED message when the IPC determines that the coolant temperature is greater than 128°C (262°F) . The IPC receives a class 2 message from the PCM indicating the coolant temperature.

LOW COOLANT
The IPC displays LOW COOLANT message when the IPC detects a low coolant level condition from the PCM. The IPC receives a class 2 message from the PCM indicating the coolant level.

REDUCED ENGINE POWER
The IPC displays REDUCED ENGINE POWER message when the IPC detects a reduced engine power condition from the PCM. The IPC receives a class 2 message from the PCM requesting illumination when the engine temperature reaches 132°C (270°F).

[wally91vhevrolet]

didn't know you could pop the thermostat out of the housing, the new thermostat was in a housing. oh well. i'm positive that the head gasket it blown. bubbles in coolant which makes it foam up after it runs long enough. also loosing coolant regularly with no visible leaks so it has to be internal. I'm tired of working on the truck. He's going to trade it in.