1389381 Plate-Spacer Fits Caterpillar ModelsOne New Aftermarket Replacement Spacer Plate for Caterpillar (Cat) 3406E C15 C16 C18 Engines This engine block spacer plate is a cylinder head component used during engine overhaul and rebuild on Caterpillar 3406E, C15, C16, and C18 series diesel engines. The spacer plate seats between the cylinder block and the cylinder head and is designed to maintain correct liner protrusion critical to achieving a proper head gasket seal. This 0. 003 inch