The upper radiator hose collapses when the engine gets cool. A defective "cap" is the most likely cause.
The most widely recognized reason for radiator hose collapse is a vacuum issue caused by a defective radiator cap. Caps are evaluated around 14– 16 psi. Under ordinary conditions, tops should discharge the negative weight caused when a motor chills off and the fluid coolant contracts. They do lose their rating following quite a while of utilization or in some cases they basically turn out to be excessively messy, making it impossible to work. In these cases, everything necessary to settle the issue is another cap. Simply ensure you supplant the old one with new cap of a similar pressure rating.