I dont think it makes any differance hot or cold...

depends what grade of loctite used. if your only using 243 or similar thread locker it wont matter, should be able to undo with spanner or socket etc. but some of the higher grades such as 680 super high stregth retainer or bearing lock u will need to apply heat such as oxy torch etc. hope this helps. cheers

I have to use a heat gun to get the red locktite off otherwise you just mess up the bolt, cause they just will not budge.
Blue locktite is a bit easier but applying the heat makes em all easy.
Heat gun or even a hair dryer (not that you would have use for one of them Steve) is probably the safest just don't get to close to ya paint.