Originally Posted By: jmacd
Newbie here, I have a 2015 Ford F250 PSD and tow a 7,000lb. TT 6-7 times a year. Tow on the Coast, in the Sierras and Cascades. I have 18,000 miles on the PSD and after the first OCI switched to Motorcraft 15W40. I'm approaching my next OCI and have a dilemma. Stay with 15W40 which seems to be "old school", go to synthetic 5W40 which is "spendy" or return the factory fill 10W30. Why does Ford consider trailer towing in excess of 1,000 miles severe service requiring 5W40? Can I run 10W30 year round?
I have a feeling that Ford is attempting to circumvent an "Ecodiesel" type situation by recommending a heavier weight, with NO CK-4 rating, for long distance towing & HD usage. Now, if you wanted to lock out OD or not use 6th gear on a manual, keeping the RPMs well above 2000 all day long, I bet the 10W30 would be just fine. I'm not the biggest fan of Ford engineering, they've made a lot of mistakes (see the 6.0/6.4), but I'm inclined to trust them on this one. BTW, if you time your purchases correctly (rebates, etc.), Delvac 1 ESP 5W40 & Rotella T6 can be gotten for a reasonable price-heck, I bought 50 individual quarts of D1 5W40 a couple years ago when AutoZone was (stupidly, IMO) dumping it for $1/quart.