In my 2006 chevy impala . the temperature gauge keeps reading turn a/c off eigine hot and the car could have been running for 20 minutes for the day

If the coolant level is low in the engine it can cause heat fluctuations from the heater, as well as an incorrect reading on the gauge. Make sure the coolant level is correct in the engine.

So did you check the gauge and the sending unit ?
Either component could be faulty.

first check your water on radiator if is not full you may have a water leak.

fans came late on those car,like 212 and second fan comes on at 224,you reprogram it to come a lot sooner,,other thing is there might be gunk inside the block,and coolant has hard time to pass through,and staying longer than enough in block temp goes high,even tough the radiator is doing it's job,it is just coming out block lot hotter than it suppose to be,and gauge read the block not the radiator

yea they are right right undo the hoses from the coolant container to to the radiator and the hose from the radiator to the engine and let it all drain out then put it back on and put some new radiator fluid in the radiator until ist full and then put some more in the container for extra make sure to put both hoses back on

After much research the only answer I found was to change the Heat Sensor. This is the problem we just had last week.

there might air in the system so you will have to bleed it or remove the rad cover and let the car run for a bit the should be on in full

heater core could be plugged up. flush cooling system.

your coolent level is WAY LOW , fill the radiator before you go to Tonys house today...
The fan was running cuz the engine was VERY hot...

YOUR ACTION IS REQUIRED:
If the engine is not really overheating and not low of coolant.
IF IT IS DO NOT CONTINUE TO RUN THIS VEHICLE.

RECOMENDATIONS: Sight unseen.

Replace the temperature sensor.

The Failed temperature sensor has a zero reading for the Control board, without this reading the car starts running in limp home mode or Default and assumes the engine is running hot, first thing to go is your comfort... The AC.
In addition starts the engine cooling fan to running full time.

Hope this tip helps.

r/
David