Possibly, i'd check the flap was opening and closing properly, otherwise you might end up struggling over the matrix and find its no better. The coolant flow through it should be continuous, if it was blocked usually the out pipe would be cooler/cold (depending of course on how blocked it is).

Whats the cooling system like condition wise, any signs of over heating/negligence (like orange stained bottles, orange stains on the engine bay around the bottle, and brown sludge in the bottle)