it happened after my expansion tank cap cracked. I've bled it about five times already so i think i got all of the air out of it. and its a manual. Oh and i completely forgot, i haven't be able to get heat for about five months. I replaced the heater valve with both a new valve and just an open "U" and is till couldn't get heat. I don't know if that could be a symptom or not though.
Stupid f**king plastic parts!