Ron,
I just stopped by the dealer parts counter, the parts guy told me that when the water pump is starting to go bad, the coolant will ooz out of the weep hole. Then it will just drop dead any time. It's funny that the water pump was making some loud chirping noise every now and then in the last 2 months while the engine is running. Perhaps that's the tell tale sign of failing. I still don't know what the brown stuff is or where it might come from. Will post more info when I get to replace it.

On a separate note, would the tires wear out unevenly (more the outer edge) if the shocks/spring is weak? My rear tires are wearing out quicker on the outside then inside (an alignment was done 5000miles ago).