Having an issue bleeding my 00 Grand Cherokee 4.7L V8 Engine.

I just recently changed the heater core on my jeep, got it put back together and went to go bleed the system using the bleeder screw on the elbow of the upper Rad Hose, only to snap my Alan Socket in half. So needless to say the screw is in there really well and won't budge. I'm worried I'll end up stripping the Alan key if I keep forcing it off. Are there any tricks to getting these screw off with out stripping the head on it.

Would hitting or with some PB Penitratinf Spray and some heat from a propane torch help me losen this stuck on screw?

Any other tricks one can try to loosen the stuck on screw. It appears the previous owner applied some type of red thread tape or RTV Silicone to the threads which is apparent when inspecting it.

 

heat works well if you can get in there without damaging the surrounding surfaces. I prefer liquid pipe sealant as people overtorque the tape version and then its hard to remove.