LUBRICATING SYSTEMS Most marine diesel engines are pressure lubricated, the pressure being supplied by a gear-type lubricating oil pump located in the oil pan or other location on the engine. A pressure regulator is used to control the lubricating oil pressure. Filters and screens are provided in lubricating oil systems to remove foreign material from circulation and to prevent damage to bearing or mating surfaces. A bypass valve is provided in the full-flow oil filter head as insurance against interruption of oil flow by a dirty or clogged element. Maximum cleaning and filtration are achieved through the use of both bypass and full-flow lubricating oil filter. Full-flow filters are used on all turbocharged models of marine engines and are optional on most other types of engines. Some engines are equipped with special oil pans and filters for some applications, and others are equipped with auxiliary oil coolers to maintain closer oil temperature regulation. Turbochargers are lubricated and by the same lubricating oil in most cases, while fuel pumps and injectors are lubricated by fuel oil.