4.Notice the slight difference between the left and right rocker arms. The right, driver-side rockers are darker than the left, indicating the right head may have been subjected to more heat than the left. There were also large amounts of calcium around the water jacket of the right head. This is why you don't want to just put water in the cooling system. The calcium deposits obstructed the coolant's flow through the right head, which allowed that side of the engine to run hotter.