This will teach you. Almost everytime I change coolant either a hose calls it a day or something else does in a short period of time. First thought in my mind is there goes my fresh coolant followed by where is it coming from and then why me. But normally in my case if there are say three ten dollar hoses in the system and one that costs a hundred dollars and is not in stock locally you automatically know the hose that has failed. I try to check the hoses everytime that flush and refill is done. The on board computors must have a sensor that tells the cars cooling system to fail soon on the sucker after recognizing new anti freeze. Who knows?