Originally Posted by got3fords
I don't think I've ever owned a vehicle that didn't have some crap on the bottom of the coolant cap and/or accumulating at or near the fluid level. You have to realize that as the coolant gets hot, contaminants boil off and accumulate at the highest point in the system. With a new engine, this could be a number of things, assembly lube etc. The fact that its in the tank means its no longer necessarily circulating through the engine. Even if it was, its just mostly coolant with a little oily stuff.
Having said all this, I am not saying there isn't a problem. Just that I wouldn't be too concerned.
This post is so ignorant it makes me mad. Firstly, do you understand what boiling is? It is a process in which water evaporates and turns into steam. The only thing that is going to be carried up onto the radiator cap is H20. Any solids would be to heavy and remain in the coolant. *End Rant*