I noticed that the upper radiator hose on our 1999 Forester (60k miles) was collapsed after the engine cooled down. There are no other cooling related problems. Both head gaskets, water pump and thermostat were replaced in the past year under warranty. The radiator cap is still the original. Is the problem the age of the hose or some other cooling issue? Thanks.

 

You are low on coolant. I also recommend replacing the stock hose with something more durable and heavy duty. Like the SAMCO's.

 

replace the radiator cap.