I have a 95 camry LE (6 cylinder) that has a major overheating problem. I managed to rule out the thermostat, leaks, radiator, and fans as the cause of the overheating. But the water pump has me stuck...On my engine, I have to take off the whole front of my engine to get access to it, and it is driven by the timing belt. The timing belt is fine, old (16 years, I bought new one today) but still doing its job. Being that the water pump is belt-driven, how could the pump fail to circulate coolant? If the belt spins the little pulley, the fan inside the pump has to spin too right? Am I missing something here?
Well, I need to do more studying before I post here. I was under the assumption that the teeth-side of the timing belt was driving the water pump. In fact, the smooth side of the belt is driving the pump, and especially if the belt or pump is very old like in my case. It is possible that the belt is either not causing enough traction to move the pump or the pump is stuck, and can't be moved by the belt.
I had this issue on one of my cars. The impeller on the water pump was plastic and had cracked. The timing belt was spinning the pulley, but the impeller was not necessarily spinning. The new one I put in was metal.