Q: What would make a radiator hose to collapse?
A: Radiator hoses sometimes have a reinforcing spring inside that helps prevent radiator hoses from collapsing. If this reinforcing spring is faulty or missing, the hose may collapse when there is a vacuum in the cooling system. Another cause could be a faulty radiator cap. A radiator cap works to maintain a constant pressure in the cooling system. As the antifreeze mixture begins to cool after engine shutdown, a vacuum is created. If the pressure cap doesn’t equalize this pressure, a radiator hose can collapse. The small vacuum valve in the radiator cap may not be working properly.