03 F250 Super Duty 7.3L D oil change interval question

[craftyone]

170K miles.
Was a light tow'r from 0-40K, now just a light duty chore truck.
Now that I bring my rig home it doesn't see highway miles either.
Was using Rotella until couldn't find it.
Now using Super Tech 15w40 HD Diesel w/ Motorcraft filter.
Was changing every 3000m but have seen some talk about going 6-7500k on conventional and 10k or more on synthetic.
Is this about right? Would I be pushing it with the cheaper oil to go to 6K?
The future of this truck is basically throwing a camper in the bed and bringing it to the camp with occasional runs back home (1.5hours) for any maintenance.

 

[Creekside]

April and October unless you put on more miles. If you are putting 5k plus on in 6 months then I would go 5k. The HEUI systems really like fresh clean oil.

 

[ripcord]

The HEUI systems really like fresh clean oil.

What Creekside said. These go a long, long time on plain old 15w40. I would keep rolling like you have been and change it at 5k or less intervals. The fuel injection system is driven by engine oil pressure and it doesn't like it to get too dirty, so keeping the changes closer together is best.

 

[mblgjr]

What they said.

Have a 7.3 in service at 160k; always on Rotella T4 15.40 except for a few winter changes of 10.30 occasionally in its life.

Definitely would not exceed a 5k service interval.

 

[bullwinkle]

The HEUI system is not a huge fan of long OCIs-I would use the cheapest quality 15W40 HDEO I could find & change it at 5K, or once a year. The HPOP & fuel injectors shear the oil.

 

[AJB0009]

I have a cousin with a late 90’s 7.3, electrical contractor. Has a loaded trailer behind it ninety percent of the time. South FL heat. 480k miles. He has only ever used T4 15w40.

 

[KJSmith]

I put 304k on my '02 7.3.
T4 15w40 at 5k.
Best engine I ever had.
Transmision service every 30k.

 

[bbslider001]

Nothing to add. ST is a good oil. I have used it for severe conditions and had UOAS done. It is a very good conventional oil. 5k on all my 7.3s and never had an oil issue...injectors, HPOP....nothing.

 

[Sword_of_the_Spirit]

Supertech or Costco stuff. Could get a ton of 1300 15w-40 from Mobil when their rebates kick in.