Hi I have a 2012 2.2 diesel Captiva with a engine issue. Problem is that engine oil is is making its way to the coolant and overflowing from the coolant expansion tank. Nil coolant present in the engine oil (Has been drained and refilled to make sure). Vehicle does not overheat and starts and runs as it should. I strongly suspect the oil cooler is to blame although cannot find were it is located in the engine bay. Where is it located and can it be replaced with the engine still in the vehicle.