PURPOSE: To provide a homogenous lubricant additive for an engine excellent not only in cleaning properties but also in film forming action and lubricating action and not substantially containing particulate matter.
CONSTITUTION: A substantially particulate-free homogenous lubricant additive contains about 0.33-0.46 wt.% of a first nonionic fluorochemical surfactant selected from the group consisting of a fluoroaliphatic oxyethylene adduct and a fluoroal1phatic oxypropylene adduct, about 0.35-0.40 wt.% of a second oil soluble nonionic surfactant and about 94-99.4 wt.% of a transport medium over a range from light oil to grease. An antioxidant a petroleum distillate solvent, a sterilizing agent and the like are additonally used in the additive.