Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance where would it be coming from?

Just clean it off with degreaser and a hose, then leave it a while and look to see how quickly it occurs again.
You could be getting a bit of oil from the valvecovers leaking down and some from the crankpulley shaft seal in the front. Most likely it is oil being flung up and around from the crank pulley shaft seal. Not a big deal if you just clean it.