Yes heat but the blue 242 will break free if you can apply enough force to the part.
Also as Hillrider mentioned it take some time to set are you sure it's not cross threaded?
BB threads are very fine and if not careful can be cross threaded quite easily.
I might add I have never needed to use Loctite on a BB.
Last edited by JTGraphics; 08-20-14 at 10:52 PM.