2004 Sierra 1500 Engine coolant hot

[Lucas Eppard]

I have a 2004 Sierra 1500 5.3L with 190k miles. Just replaced the water pump, thermostat, and coolant temp sensor. Two days later the “Engine coolant hot” and “Engine overheated” warnings came back on. Checked engine at idle with a temp gun and again after the error started beeping. Same temps both times and not at a temp that should be giving an overheating warning. Any ideas?

[Ian Mills]

Does the gauge show overheating temperatures?

[Lucas Eppard]

No just the DIC and alarm keeps going off

[CamGTP]

Could be a bad new sensor.

[Ian Mills]

16 hours ago, CamGTP said:

Could be a bad new sensor.

Wouldn't that cause the gauge on the dash to show a bad reading too? Or am I missing something?

[Sharpz]

On 5/13/2021 at 5:31 PM, Lucas Eppard said:

I have a 2004 Sierra 1500 5.3L with 190k miles. Just replaced the water pump, thermostat, and coolant temp sensor. Two days later the “Engine coolant hot” and “Engine overheated” warnings came back on. Checked engine at idle with a temp gun and again after the error started beeping. Same temps both times and not at a temp that should be giving an overheating warning. Any ideas?

being that you changed the WP, Thermo, and Coolant temp sensor your problem might be air in the system. Did you change the coolant temp sensor while the truck was drained of coolant or did you do it after while it was full?  Someone suggested to me that coolant might have got on the connection and that might give a false positive reading.  That wasnt my issue, but you may want to look into that too.   Back to air in the system. If you get pockets of air, it can cause all sorts of issues because lack of flow through the system Try getting different readings in various parts of the coolant system, or just go back through the bleeding system and see if you have some air still hanging around.  Make sure you have the heater on high while doing the bleed sequence.