If the temp gauge didn't go past the half way point you don't need a new engine. I had the same problem. I noticed that the coolant level went down a bit on the overflow I filled it back up then I heard a leaking sound when I was filling up at the gas station. I filled it back up with the anti freeze that I had bought from the dealer and took it to them. The first question they asked me was did it overheat and I told them no. The water pump was replaced and so far it has been okay. I am still not happy with this design as the engine has to come out for this to be done.