Volkswagen Repair: 99 New Beetle, water pump impeller, new beetle

Question
I have a 99 New Beetle 2.0. It has started to overheat. The cooling fan does not come on. It has 86k miles. Timing belt has been replaced, but not the water pump.  Any idea what may be causing this? Temp sensors? Coolant is OK.
MB

Answer
If the system is actually is overheating then the broken water pump impeller is most likely the problem. Fans is second and the thermostat is usually the last of the likely cause. Good luck read the answered questions of over heating and cooling fans.