Oil system for aircraft engine having features to prevent drainage of component

An aircraft engine having a centerline, comprising:

• an oil system including:
• a component located above the centerline and having an inlet and an outlet;
• an oil circuit fluidly connected to the component, the oil circuit including an input line fluidly connected to the inlet and an output line fluidly connected to the outlet, the input line defining an input U-shaped section, the output line defining an output U-shaped section;
• a valve fluidly connected on the input line or the output line, the valve located between the component and a respective one of the input U-shaped section and the output U-shaped section;
• and
• an anti-siphon line fluidly connecting the input line to the output line, the anti-siphon line defining a flow path of a lesser flow circulating area of the input line and the output line, the input U-shaped section, the output U-shaped section, and the component located between connection points defined between the anti-siphon line and the input and output lines.