what type of oil

use mobil synthetic 10w30. just remember that synthetics usually uncork some leaks and add a little valvetrain noise if you dont have it already. I run Mobil Clean 5000 in mine w/ a motocraft filter and change it every 3k miles.

If the car has been run with synthetics for a while by the previous owner, I dont think youll have a problem. Most that report leaks switch from conventional to synth with high mileage and the detergents in the synth eat away at the build up that may be sealing up some leaks that you would otherwise have.

If its been run with synth for a long time, it probably doesnt have that build up.

I use conventional Rotella T 15w40 in mine.