yes, the water/radiator Fluid is what its pumping thru there, the fluid gets hot when it enters the motor and gets cooled in the radiator. The Pump on some older cars is where the fan is connected.
There is also usually a little hole on the bottom side of the rotor/shaft, you usually see a rusty run going down the front there, like sometimes in a old bath tub that leaks. hehe
Bmr4life, I feel stupid all the time, does this help.