I have replaced the thermastat & got a new radiator cap. Done a do it yourself flushing system. With still these problems. Just replaced water pump same issue. Over heats & at idle with no heat while hitting gas temp gauge drops & I have heat. Done the 2 bleeders on them and its on & off. Sometimes I have a steady flow other times it spits out alot of air. I have let it run till had a full stream shut it off let it cool down & still nothing.