The invention relates to a method for lubricating an expansion machine (30) in a thermodynamic cycle device, wherein the thermodynamic cycle device comprises the expansion machine, a feed pump (50), a lubricant separator (10) and a working medium containing a lubricant, and wherein the method comprises the following steps: The working medium is subjected to pressure by means of the feed pump. The pressurized working medium is delivered by the feed pump to the lubricant separator. At least part of the lubricant is separated from the working medium by means of the lubricant separator. At least part of the separated lubricant is delivered by the lubricant separator to the expansion machine. The invention further relates to a thermodynamic cycle device comprising a working medium that contains a working fluid and a lubricant, an expansion machine, a feed pump for subjecting the working medium to pressure, and a lubricant separator for separating at least part of the lubricant from the working medium, wherein the cycle device is designed to deliver at least part of the separated lubricant from the lubricant separator to the expansion machine.