I am trying to figure out where the engine coolant sensor is located?

The block is an 2008 which was the year Chevrolet moved the sensor to the back of the head. But my head is an 2002 which does not have the port in the back of the head. But can I remove this plug and use it instead? The first picture is the 2008 motor the second is the old 2002 block.

Sorry first and third pictures are the 2002 block second is the 2008 block.

Now I see the old sensor in the old block but the hex plug is what I am talking about here Roy. I know it is for water but it is okay to use it instead?

Yeah, I was thinking reducer to the sensor size.

Locate temp sensor on motor