Frozen Vent Plug?
I have a 1993 T-Bird with the 3.8 engine.
After reading the forums, I decided to try the described 3.8 engine radiator-flush procedure. The problem is that my vent-plug is frozen tight.
A few years back, I also tried to change the coolant with out freeing the plug; and I'm sure I came pretty close to seizing the whole engine.
I have tried using Liquid Wrench, letting it soak for 24 hours, and tapping with a small hammer, to no avail.