Re: WATER JACKET
The water jacket is the water in the cooling passages that surrounds the cylinders and also the cylinder head. When someone refers to the water jacket they are talking about the surrounding coolant. On some cylinder heads there is a separate cover plate with its own gasket that allows inspection of the cylinder head cooling passages or water jacket. Removal of the cylinder head does not require removal of the water jacket cover. Removal of the water jacket cover does not require removal of the cylinder head. They are both separate.
