Lesson 1/Learning Event 1
The cylinders of the liquid-cooled engine have jackets all around them to hold the cooling liquid. These jackets
are made with, and are a part of, the cylinder block. Passages in the top of the block allow the coolant to pass
between the block and the cylinder head.
FIGURE 18. CYLINDER HEAD.
The cylinder head contains the upper half of the combustion chambers and is bolted to the top of the cylinder
block. It contains coolant passages that align with the coolant passage in the cylinder block. The head also has
a threaded hole in each combustion chamber for spark plugs to be screwed into.