CHECK YOUR COOLANT LEVELS!!! I lost a water pump on a Subaru one time cause the engine warmed up but no heat inside. About 15 minutes later, the temp guages spiked and I pulled over and the radiator took 1 and 1/2 big bottles of premixed coolant to fill back up. Turns out it had a crack in one of the radiator hoses and was leaking slowly. Once it got down low enough, it overheated and the waterpump destroyed itself. I'm lucky the headgasket survived.