My wife and I just got '03 Mustang GT's (4.6 liter engines). So far I have changed the oil and filters on both engines at around 500 miles. For now I am using Motorcraft 5w-30 instead of the 5w-20. When they reach 3000 miles I will switch both of them to synthetic oil. My car will see some agressive driving from time to time but not too bad. My wife's car will be driven normally most of the time (unless I'm driving it). I'm willing to take my chances with the warranty issue by not using the 5w-20. I just want the best protection for my engines. Reguardless of which brand/weight of oil I use I will go no more than 6 mos./5000 miles between drains. I had planned to use Amsoil 5w-30 with an Amsoil SDF-11 filter but I am open to other suggestions from you more experienced guys. Any recommendations?
[ April 19, 2003, 12:22 AM: Message edited by: Keith B ]
[ April 19, 2003, 12:22 AM: Message edited by: Keith B ]