Originally Posted by ballitch
Probably not the thermostat, but it is definately the one gauge you want to have with that motor...
That's an understatement! But yeah, I replaced mine and you can do it without removing the intake manifold. It's a pain in the rear though, and it would probably be worth it to just undo the intake man. bolts so you have some wiggle room. It's the larger of the two sensors on the coolant pipe. All of mine have been red. I used a mid-sized extension and a deep socket.
The smaller one is the thermoswitch for the primary fan, I believe.