Coolant Expansion Tank Query

Just picked up my wifes Freelander 2 (2007) and the car drives like a dream. However when going through the 'under bonnet' checks I noticed a slight layer of oil on top of the coolant. I have removed the tank and cleaned everything out so I can keep an eye on it but does anyone know where the two small black tubes that plug into the top of the expansion tank come from ?

Check the oil cooler for leaks - not an unknown failure on that age of car

t4van,

Thanks for the response, can you elaborate on the location of the cooler unit and whether there is a quick way to check this problem out