An engine assembly includes an oil pan having an oil pan body. The oil pan body includes an inner pan surface defining a cavity configured to collect oil and an outer pan surface opposite the inner pan surface. The engine assembly further includes a heat exchanger disposed within the cavity. The heat exchanger is submerged in the oil collected in the cavity of the oil pan and can receive a heat transfer fluid in order to facilitate heat transfer between the oil in the cavity and the heat transfer fluid flowing through the heat exchanger.