The Water Pump is the most critical component in your vehicles cooling system. Without it working you are quickly left with an overheating engine and the possibility of needing a new one. The water pump on a four cylinder engine is usually located internal and is driven by the Timing Belt. Manufactures usually specify a replacement interval between 40,000 and 110,000 miles depending on the vehicle. This is usually something that should be changed out with a Timing Belt so as to not pay for the labor of opening the motor up twice.