That's great the overheating is fixed. I wonder if you just need to purge the system again. My Vee has never bubbled in the over flow that I have noticed. I may be wrong- but I would only think that was normal if there was air trapped in the system.. Maybe it doesn't hurt anything, but odd for sure..
If you give a Moose a Muff..ler...
Its a Kid thing
Next time I'll put some effort into my username. This one sounds like a toilet Bowl cleaner or Treadmill, or..