2003 Toyota Camry Confused

I'm in the process of buying this car and when I test
driven it, I began to hear what sounded like water running behind the dashboard. I wasn't using my ac. So I decided to look up some problems with this type of vehicle on line. After researching this problem. I found out that several customers have experience the same problem with their vehicle and when they reported to the manufacture and to make a long story short, they had to replace the engine. With your expertise with vehicle, should I pass on this vehicle? Was the running sound was actual the sound of a bad engine?

waiting for your reply. Thank you