These studies
indicate that the oil drain period for gasoline
engines could be increased considerably from
10,000km recommended for many gasoline
engines in production by use of an optimised
filtration system and superior quality synthet-
ic oil, up to 30,000km which is currently
under consideration in the European automo-
tive industry. Note that for long oil drain
periods the engine would still require oil to be
“topped up” in between each oil drain to
account for the oil consumed.