My car is having over heating probs. It only happens while driving it can sit and idle all day long. New water pump and tstat. Flushed radiator and hea ter coil. Replaced radiator cap. And new temp sensor. Burped it 3 times to get air out. Top hose is hot bottom was much cooler. Could it be a collasping bottom hose. Noticed the coolant tank was jumping a little when it pulled water out.. any help ..heater stops bl8wing hot air once this uappens. If that helps any.