Just put in 5qts Pennzoil Platinum and a half quart of MMO with Motor craft filter. Car has had a steady diet of syn blend motor craft its whole life. Has 145,000k and all is good. Also has a new pcv valve.
Same exact combo I'm running in ours. We have close to 90k on it. No need to run a 30 weight with MMO the PP. If the MMO does happen to thin with PP the Duratec's prefers thin. And I've noticed since I've added MMO on top of the PP is does seem to rev up quieter and quicker. Can't say anything about gas mileage yet.
I dunno... Having a Chlorinated solvent which thins out the oil below its normal weight would have me cringing at the thought of the bearings running without a proper cushion of lubrication.
If Ford wanted thinner they would have specified such IMO.
If there were a thinner "Motorcraft" oil I'm sure they would. Sure you can get 0w20 now but there's not a MC version and wouldn't make good business since to recommend another brand unless they own 'em.