So in the midst of my winter modding / maintenance I am prepping to check the valve clearances. I removed the rad to allow more room and while the coolant in the overflow bottle looked good and clean, this is what came out of the rad;



I went ahead and removed the water pump cover and it seems to look OK in there, other than the dirty water.

I did an oil and filter change at the end of last season and neither showed any sign of water infiltration.

My questions;
If I jamb a water hose into the cooling ducts will it come out both at the upper and lower hoses?
What are the pro's thoughts about continuing onto a water pump rebuild at this point?
And if I am going to do the pump, couldn't I just leave the impeller in place and remove it when I can secure the shaft from the inside when the side case is off?