Where is my coolant temperature sensor located on my 2006 Pontiac Torrent

It is likely to be neither! It was running at the correct temperature before, so all was good, you just has a leak that needed fixing. Your problem is likely cause by air in the system which is preventing coolant circulation. Make sure your radiator fans come on once the engine comes to temperature, as the coolant sensor must have been removed.

https://www.fixya.com/cars/r29872074-vehicle_cooling_system_no_heat

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The engine control module (ECM) calculates the engine coolant temperature as determined by the coolant temperature sensor. The ECM sends the engine coolant temperature to the body control module (BCM) via the serial data circuit. The instrument panel cluster (IPC) displays the engine coolant temperature when the BCM sends a serial data message to the IPC indicating the engine coolant temperature. The engine coolant temperature gage defaults to 0° or below if:
• The ECM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM

The place to start would be to hook up a factory or professional scan tool to see what the actual coolant temperature is ! At the PCM then at the BCM and finally at the instrument cluster . If normal the gauge is bad . The instrument cluster would need to be taken out of the vehicle an sent to be repaired . Or you could buy a used one out of a salvage yard or from on e-bay etc....

Engine Coolant Temperature (ECT) Sensor
At the rear of the engine cylinder head, below the brake master cylinder

Hi Regina video on where your battery is. Battery Replacement 2006 2009 Pontiac Torrent 2006 Pontiac Torrent 3 4L V6

Ambient Air Temperature Sensor (UH9)
At the front of the vehicle, at the lower left side of the front bumper bar
Ambient Air Temperature Sensor (UH9)
Pin
Wire
Circuit
Function
A
0.35 L-GN/BK
735
Ambient Air Temperature Sensor Signal
B
0.35 YE
61
Low Reference

Locate it near the thermostat. Which is on front of the motor following the the top radiator hose back to the motor . It stops on thermostat housing. The temperature sensor is in the top of the motor it's got a single plug wire with 2 wires in it. Unplug wires use a wrench turn it to the left unscrewing the sensor all the way out using Hi-tech review from the auto parts store red in color apply to the threaded end of the new sensor. Plug in the wires give the Rtv.time to dry. Remove the radiator cap check the coolant level then check the side of over - flow tank also level is marked on the side with a line that says high cold put radiator cap on pushing it down an turn to the right. Hope you are helped by this

On left end of rear cylinder head

The temperature gauge is actually a needle that read a range of Hot/Cold on the dash instrument cluster. If you are referring to the coolant temperature sensor, the location depends on the engine size. Post the engine size and we'll answer it better.

no just lower the level or be quick about plugging in the new sensor, that is what I do, u may lose a cup of coolant but much less hassle than draining the radiator.

Another possible cause is your coolant sensor. if the sensor goes bad, it will drip coolant but won't notice it because it just seeps down the engine components. Most people don't even realize that there is such a sensor. it will send a faulty reading that its overheating when the coolant level is fine and when enough coolant does seep out it will still say its overheating because it is at that point. I would definitely look into checking your coolant sensor as the cause since it's so hard to even see that it is leaking and its super easy to take out and replace. hope that helps if you're still having problems