- Joined
- Dec 30, 2006
- Messages
- 29,558
What's the thickest oil anyone has used in a Ford 4.0 V6 (2007 Mustang)? Of all the oils I've used in it,so far the "thickest" 10W30 has been the smoothest. Synths make it feel loose and sloppy. Thinking about trying a mineral 10W40. Anyone ever use or try a 40 wt oil in one of these engines? I was thinking someone here did but I can't remember who it was.