brown/ tan discoloration of antifreeze in radiator.

What is your question?

12-02-10 bought truck so doing maintenance tune up opened radiator cap anti-freeze was tan brownish color. opened all radiator hoses and flushed it but top radiator hose going from radiator to engine antifreeze is not flowing in to engine watercomes right back out thru hose. thought it might be water pump? and hoping tan/light brown discoloration in radiator is not oil? help please jwkjr1@hotmail.com