Just putting this out there.
Recently replaced a water pump and to my surprise the impeller had rusted almost all the way off. this issue also caused overheating and coolant loss into the oil.
as well as I had to replace the heater core due to internal blockage.
I have pictures posted here on flickr of the damage
it is extensive as you will see!!!!!!!
http://www.flickr.com/photos/11809460@N00/sets/72157618565943833
total damage was:
Water Pump,Thermostat,Timing Chain Cover,Gaskets,Heater Core,2 Hoses. as well as oil and coolant replacement.

Thanks for the photos. This is a common issue that has been addressed on this forum a few times in the past.

-Rod

Thanks for your reply I was happy to post pictures due to the extensive damage the water pump impeller had caused.:banghead: