My '99 century limited has a pretty severe coolant leak on the driver side directly under the rear valve cover (so the one furthest from the front of the car). The leak is coming out of a really hard spot to get a picture but the 2nd picture was the closest I could get. The hole has a slightly tapered entrance that measure 0.945 inches at the smallest, and a second threaded hole right below it (hence why I think a sensor popped out).

Apologies for the crappy pictures, if anyone has any schematics of the driver side engine I would also really appreciate that as I could probably figure it out since I've spent so much time looking at it.

Any advice would be really appreciated. I am pretty much at my wits end trying to fit different things in this hole.