Q: Why Do Hoses Collapse?

Hoses undergo a variety of system changes during normal engine operation. When the engine is completely warmed up, pressure inside the cooling increases to around 18 - 20 psi. This causes the hoses to expand.

One hose in particular has a tendency to collapse. This hose is the suction hose for the water pump. The water pump causes a low pressure area to form in the hose connecting it to the radiator. To prevent this hose from collapsing due to low pressure, a wound wire spring is inserted into the hose near the water pump. This wire provides internal support to the suction hose, similar to the frame of a house.

Another cause of collapsing hoses is a cooling system that is low on coolant. When the engine is warm, cooling system pressure increases. However, when the cooling system cools down, the air volume inside the cooling system draws into a vacuum which causes all hoses to collapse.

Periodic inspections of your cooling system, coupled with servicing hose components that are soon to fail, should prevent any hose from collapsing. If you need any assistance with this, reach out to a professional mechanic who can inspect and replace your hoses if necessary.