2020 F350 6.7 with 6k miles and Amsoil dual remote filter. Daily city driving, weekend towing 8-11K #

Our RV is supposed to be done anytime now. I have 6K on the OEM 10w-30 and will be due for an oil change soon. We will be driving empty from CO to OR and towing back to CO. I would like change the oil to the severe duty 5w-40. While I get an Amsoil discount I have no plans on extended oil change intervals. Any problem switching to the Rotella T6 5w-40 and running about a 7500 MAX OCI? Here in CO we can have huge temp swings. The T6 seems to fit the bill as readily available and inexpensive. Thoughts?

 

Rotella T6 did fine in my 2015. I had been using the Valvoline 5w-40 PBE but it makes a whining noise underneath the cab about 500 miles before an oil change is due. The T6 didn't seem to make this noise. In my manual, it says the 5w-40 is required for any use of biodiesel or any kind of towing. Not sure what the 2020 says.

 

I can't say I've ever heard a whining under my 16 that was due from the upcoming oil change. I would get whining under the cab from priming the fuel filters when I changed them; at the DFCM under the driver's side.

I use MC 10w30 with fuel that's up to B5. I've had the oil analyzed and had no problems with viscosity at all. But I don't tow either. I know @FishOnOne pulls a camper, uses MC10w30 and has a lot of miles on his with zero problems. I'm sure the 20 plus manuals says the same thing.

But I'm also not saying going with a 5w40 for towing is bad either.

 

I would choose Rotella over Amsoil every single time.

 

I used to be a Amsoil dealer. I am a fan and Amsoil is a great product but I agree with you. Rotella in my 6.7 every time.

 

If you are sold on 5w40, Rotella.
My second choice would be Providence from Rural King.
An excellent 5w40 sleeper from Warren, and sold under their house brand. Significantly less than Rotella unless chasing or catching a (really good) sale.
But why 5w40?
Simply not needed unless cold starts below say 20 degrees.
10w30 does very well in the 6.7
15w40 does very well in the 6.7
It's not picky. Lots of used oil analysis show 10w30 does just fine with B fuels and towing, and squeezes out a few more 10th's in MPG.

 

I haven't run an OCA with T6 for ages because I haven't been towing much. maybe next change. I have the full report somewhere I have to dig up, but if you click the timestamp at 3:44 you can see an excerpt from Blackstone:

 

Yep... 217,000 miles on Motorcraft 10W30

 

That a boy...

 

The cheapest 10w30 on the Ford approved list is what we are allowed at work. Never had a oil related failure. It's normally a toss up between MC or Citgo. Figure a few thousand trucks company wide so price matters.

 

You would know for sure. Appreciate your experienced input. How many 6.7s you guys run?

 

Well currently we have about 2500 of them, some as old as 2015. We have probably had 10k 6.7 trucks come and go. I still buy oil and fuel filters six pallets at a time.We are supposed to purge 15% yearly of our fleet but covid changed that. Looking forward to the 22 trucks arriving. We just took in another 70 F-750 (30 are 7.3 Roush clean fuel equipped) trucks to replace older IH trucks.

I apply the same maintenance to my own trucks. I know sometimes emotions and gut feelings are hard to overcome. I also like the lowest operating cost especially if I can control it. i put 400k total on five different 6.7 trucks always ran 10w30 bulk and changed per the IOLM. Did lots of ALS UOA's and never a issue with wear from the oil.

 

Holy schitt... Yeah that's a lotta trucks. And oil and filters... WOW.

I know you mean the new gasser 7.3 but what did you mean by "Roush clean fuel equipped?" Or unless I'm wrong since you mentioned the International trucks which means the 7.3 Powerstroke I would think...

 

I have used T6 since my first oil change and like it. I will mention to the OP that you might not get 7500 miles between OCI’s in certain circumstances. As an example when we drove to Alaska last summer (to escape the Covid nonsense) my oil change light came on at about 4800 miles with our truck camper driving in strong head winds across Wyoming and Montana from VA. After that change it went back up to normal but the point of this is that even with full synthetic your trucks computer may want you to change it more frequently depending on your environmental conditions.

 

SMLFORD - I’ll be comfortable at 5-7k intervals.