Start by looking at Halfords at the oils list - for the 2.0litre Focus. Your handbook should specify the oil, but some handbooks are misleading.
For example - for a 2003 Focus, the oil suggested is:
Halfords 5w/30 part synthetic
Castrol Magnatec 5w/30
Mobil Super 3000 Formula FE 5w/30
Here's the link:
http://www.halfords.com/webapp/wcs/store...egoryId=165581#
