An oil separating module for an internal combustion engine, including: an oil separator, an oil return arranged such that separated oil can flow through the oil return to an oil sump, a mounting, and a non-return valve having: a valve housing having a throughbore with a first end opening and a second end opening, and a valve body movably mounted in the valve housing such that the valve body transitions between an open position and a closed position. When the first end opening is above the second end opening, the valve body automatically transitions to, or remains in, the closed position when a second end opening pressure is greater than a first end opening pressure by at least a threshold pressure difference, and the valve body automatically transitions to, or remains in, the open position when the second pressure is not greater than the first pressure by at least the threshold pressure difference.