No need to disconnect a lot of stuff. You need the right size deep socket, a wobble extension, around 10". I partially removed the intake manifold on my first attempt, and it did not give me the access I needed. I did not want to remove the injectors.

Might need to take off the accordian hose. The ECT is under the 3rd intake runner. You will not be able to see it. Find it by braille. Unclip the electrical connection. Find a way to fit (by feel) the socket over the sensor. You may need to move the engine harness out of your way, it runs vertically up/down the engine block here. Once you are able to get the socket on the sensor, attach the wobble extension. Mine unscrewed easily. Leaked very little coolant. I had to cut a few zip ties on the engine harness to get it to move, but that was easy and obvious at the time. Good luck! (my car is an '87 240).