Overheating indicator 4.3 V6 08 Silverado

[Andrew1972]

My FIL 08 4.3 V6 Silverado with 59k has overheat indicator/AC disabled on. The hose from water pump is hot while radiator is cool to touch. Fans work. The temp gauge is stuck on C never rises driving.

I can’t find a radiator cap but maybe buried under plastic? The coolant overflow is at normal level. He’s 80 so he is fiddling with it in my driveway.

Advice ? If it had a cap I could see if has coolant.

 

[hemitom]

getting any heat out of the vents ?

 

[Andrew1972]

getting any heat of the vents ?

Very hot.

 

[390pcode]

There is no cap on the radiator. You fill the coolant bottle on the pass side. Sometimes, it is hard to see the coolant level from staining/plastic discoloration. Bad coolant sensor, maybe?

 

[hemitom]

Stuck thermostat possibly.

 

[slacktide_bitog]

The coolant overflow is the only cap your truck has. If the overflow is at the correct level, you probably have enough coolant, and it's not low.

Replace the coolant temp sensor and the thermostat. Rock Auto has both OE parts at a good price

 

[Warstud]

Replace the coolant temp sensor and the thermostat. Rock Auto has both OE parts at a good price

Exactly what I was thinking

 

[Andrew1972]

Fixed , unplugged battery held brake pedal and restarted. The light is off and gauge temp jumped to normal temp from zero.

 

[Warstud]

Fixed , unplugged battery held brake pedal and restarted. The light is off and gauge temp jumped to normal temp from zero.

 

[Andrew1972]

GM is stupid in design, a code is thrown/stored and after that disables AC/shows overheat indicator in dash and pegs the temp gauge at Cold no matter if cooling system is fine or not. The indicators are fine however falsely pegging gauge to zero is poor design.

 

[supton]

GM is stupid in design, a code is thrown/stored and after that disables AC/shows overheat indicator in dash and pegs the temp gauge at Cold no matter if cooling system is fine or not. The indicators are fine however falsely pegging gauge to zero is poor design.

Wonder why they did that. Bigger indicator than a light that is more easily ignored?

 

[another Todd]

So why was the radiator cold if it was just an electrical anomaly.

 

[Warstud]

GM is stupid in design, a code is thrown/stored

You just erased the trouble code. Did you look up the code ?

 

[mattd]

All you did is erase the DTC. It will be back.

 

[Andrew1972]

You just erased the trouble code. Did you look up the code ?

I agree that happened. My FIL is stubborn and likely won't touch it till it comes back and replace the offending item.

All you did is erase the DTC. It will be back.

It might be but its my FIL vehicle and he is stubborn and the vehicle is no longer blocking my garage