someone seriously sounds like they have a BHG with all those coolant issues. BHG will put pressure into the coolant system that wasnt there before and thus cause similar probs to what you've been having.
no worries either way, BHG is far from fatal, just dont let it overheat and warp the head.
in other news, although however lowely. i finally wired up my foglights which have been sitting there for years without power. had to wire em around a bit since i wanted them to work like factory, or just be on like driving lights as the stockers used to be.