I have tried just about everything I can think of to remove the nut off of the stud that holds on the bracket that mounts to the block where the thermostat is.

I have tried PB Blaster to no avail, I bought a special socket that supposedly will remove the nut but no worky.

The only thing I can think of is drilling a hole into the stud and using an easy out tool. But it's hard to see the stud let alone being able to drill a hole into the center of it. I thought about putting another nut on top of the present one and since it would extend beyong the end of the stud, maybe it could help get the drill centered enough.

If I do in fact get the hole drilled and use the easy out bit, will the stud most likely come out or is it tightened to such a high torque the stud won't be removeable?

If I am overlooking another technique let me know or if the method I mentioned could cause me bigger problems.

I'd like to fix it myself - I have replaced the radiator and water pump and hate to fail at this point.

Thanks in advance.