Warranty Oil Changes
The oil change interval for the new Ford Focus is every 10kmiles/1year whichever comes first. Ford recommends motorcraft synthetic blend which is the reason for the longer interval. The synthetic blend will break down much slower than conventional oil.
Over time (1 year) the additives can begin to separate making the oil not lubricate as well. Therefor, even if you have only driven 1000 miles but have not had the oil changed in a year, it is time to get it changed.
As far as the warranty is concerned, as long as you change it every 10000 miles or 1 year (whichever comes first) you will be covered. If you want to, you can change it more often, but as long as it is changed by the recommended interval, you're good. Just make sure the dealership is using what they should be, which is the motorcraft synthetic blend.
Edit: Also, if you drive more strenuously than normal (high temps, high speeds, hard accel, etc.) you may want to change the oil a little more often. All these things can lead to a faster breakdown of your oil and therefor poor lubrication. This has nothing to do with warranty interval. More of an informational piece. :)
Last edited by dpotter5; 12-19-2012 at 12:51 PM.
Reason: Additional Info