2003 Pontiac grand prix 3.1l v6.
So I was tightening up my engine coolant temp sensor, and wasn't turning it hard but heard a crack. Then when I started up the motor noticed a bad drip of coolant coming from under my throttle body. You could see it dripping but couldn't see where. I also replaced the thermostat about 3 weeks ago and did not use and rtv red gasket stuff. Could that be the leak?

 

You probably overtightened something and put a crack in the upper manifold :/ with your car hot you'll probably notice a stream of coolant hissing out