Abstract: An oil detection sensor module for sensing oil leakage in a coolant system is provided. The oil detection sensor module includes a body, a membrane, and a sensor. The body includes a first end and a second end, which define a chamber. The membrane is disposed at the first end of the body. The sensor is sealably coupled to the second end of the body. A sensing end of the sensor is disposed in the second end of the body. The sensing end is arranged to detect oil in the chamber. The oil entrained in the coolant is in fluid communication with the sensor through the membrane. The membrane restricts the passage of water-soluble products through the membrane. Upon detection of a threshold level of the oil in the chamber, an alarm is signaled, via the sensor.