I contacted a rep. from Ford about a month ago. My question was if I drive the car in hot temps all the time could I run a 5w-30? They responded with "Contact your local dealership and talk with them about your oil question." So I emailed them back and said well I thought Ford would void warranties if they found out that you were running anything but 5w-20. Again they responded with the same statement. I also told them that I could care less and fuel economy and that I would rather have more protection. They would never give a straight answer, nor did they claim to void my warranty. Just Ford for thought!
Also post what oil you are running.
Also post what oil you are running.