Oil in coolant for many vehicles is a confirmation of a blown head gasket or cracked cylinder head. In the SRT Jeep Grand Cherokee, this is not always the case and many owners and technicians are condemning head gasket failure which in most cases is an inaccurate diagnosis.
The most common cause for the Oil to mix in the cooling system on a WK2 Jeep Grand Cherokee WK2, is the internal failure of the engine oil cooler.
This part is a relatively easy item to replace and genuine from jeep is not excessively expensive. Prior to condemning the head gasket, it is advised to confirm with combustion gases in the cooling system with a TK test or similar. If this test is inconclusive of shows no combustion gases in the system, it is advised to start with the the oil cooler.
Below is a short video showcasing the part, its location and a brief run through the fault on an actual vehicle.