How did you guys get the water thermosensor off? I (with great effort) managed to pull off the green plug in the tiny space, but there's not really much room for an open wrench and no room for a socket. What did you guys use? Between the vacuum lines and hardened and crack prone wiring harness connectors and wires, I can tell already this will be a massive bitch to pull off.

What size is it anyways? I was sticking a 16, 17, 18, and 19mm open wrench in the area, but couldn't even get an angle to fit it on, let alone start turning it.

 

According to some of these older posts:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/water-thermosensor-install-398679/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/changing-coolant-temperature-sensor-137972/

it is possible to change the water thermosensor (the top one on the back of the water pump/coolant neck with the green plug, not the lower thermoswitch on the coolant neck) without removing anything except a few vacuum hoses and the turbo intercooler pipe. Or so my impression is from these folks.



Here's a picture I found from an earlier thread, I circled the water thermosensor.