I'm going to stab at this one
First-how do you put an Acura body kit on a Prelude?
Second why are you posting in this forum if you have an Integra?
Don't answer
Now to the problem: You cannot see inside the water pump so I will assume you mean the tank with the hose that goes to the radiator. Better known as the overflow bottle. You are to NEVER put plain water in the radiator of a Honda-ever. It will boil out very rapidly. The solution I suspect based on the fact that your temp gauge says all is well is that you need to drain the radiator and refill it with a 50/50 mix of Honda coolant-they sell it premixed or concentrate. Use only their stuff-it has no silicates in it that will destroy your pump and internal parts. That is my opinion-and that of some pro's I know. There are other brands but they require that you fully flush the cooling system-so just do it the easy way.
If you do this you will need to warm up the engine after putting the fluid in the radiator and also filling to the lower line of the overflow bottle. Check the overflow while it is running and see if you still have fluid-if not add some. Shut the motor off and let it cool down completely. Oh-did I mention that you might want to set the heater to maximum temperature so that the valve is opened all the way while you are running the motor. Now recheck the coolant both in the radiator and overflow and top it off as needed-do not let the coolant go above the upper line on the overflow.