The water-cooled piston has proved very reliable when running on
heavy fuels and the use of water cooling has resulted in practically
negligible system oil consumption. (With oil cooling, oil is consumed
usually as a result of thermal ageing on hot piston walls. Oil leaks
from oil-cooled pistons may also occur on other engine types.) The
two-part gland seals for the piston rod and telescopic piston cooling
pipes can be inspected while the engine is running and can be
dismantled without removing the piston. The double-gland diaphragm
around the piston rod completely separates the crankcase from the
piston undersides, preventing contamination of the crankcase oil by
combustion residues or possible cooling water leakages. In addition,
the fresh water piston cooling water system is served by an automatic
water drain-off when the circulating pumps are stopped. This avoids
leakages when the ship is in port.