So my truck is about 1400 miles past the return mileage on the stick the dealer gave me last time it had an oil change (~6400 total on the oil) but the internal clock/monitor says my oil life is still ok. Which should I rely on? I usually go with the clock, but it tends to coincide more with a change every 5000 miles or so.

 

Some folks use the on board computer as a guide which is fine. I have been doing every 5,000 miles because it is easy to keep track of. I have thought of going up to 7,500 because that seems to be the computer standard for many. But, my old school training of change the oil ever 2K miles just won't allow me to do so. I do the fuel filter at 13.5K to 15K.

 

Personal preference.

 

I say personal preference. I run a 5,000 Oil Change Interval, so I don't really pay attention to either........

 

I've been going by the trucks computer. Which pops up about every 7500 miles.

I did some Oil test on my last truck, at 5,000 miles oil was good, at 6,000 miles oil was good, at 7,000 miles my oil was good. So I just started following the computer.

When the 6.7L engines first came out, a Ford Engineer who was involved in the development of the new truck was online here discussing the engine with folks. He said their test showed the oil could go 10-12,000 miles in real world use. but that they set the oil life minder at 70-75% of that number to be safe.

I've also read many articles over the past few years about how folks are wasting oil by changing it as frequently as they did in the past. The old change every 3,000 miles is just not applicable any more than to make a profit for Jiffy Lube and other quick oil change places.

I sold my 2011 truck with 145,000 miles on it, Oil was changed whenever the dash told me to. I had no problems. The choice is yours and I certainly would not think you out of line if you did it every 5,000 as the dealer suggest on their oil reminder. But I think that sticker is more about getting you back in and up on their rack, than about your oil being worn out.

 

I did similar testing over 50,000 miles as Painted Horse by changing it between 5k-6k and the conclusion I came to was switch to Rotella T6 and follow the computer.

 

If you are paying for it use the computer.

 

How does the truck computer know if you use synthetic oil or non synthetic oil...?

Reason I ask, the change intervals recommended by oil manufactures are drastically different between non synthetic and synthetic oils.

Diesel engines create the filthiest oil I've ever seen coming out of a new engine.
Can't understand the extended 7000-10,000 mile oil changes intervals the truck computer recommends for non synthetic oil.

One thread on here a while back, a member posted he did the tuner, DPF/EGR delete and now his oil stays golden clean,,, ya right, not mine. Mine is black as the ace of spades instantly, right when I check oil level after an oil change,,, black.

Sent in my last black, dirty oil sample(mobil1 5-40) to Blackstone labs, had 3000 miles on it. Oil analysis came back showing perfect. Just doesn't seem right to see black, diesel smelling oil and think it works as good as fresh oil. Suppose its good enough if the lab says so..?

I might have a rare illness, does anyone else suffer from premature extended oil change ocd,... lmao.

jmo

 

I just can't make myself run past 5k on an oil change, and it's took awhile to get there!

 

Going back to my 6.0L days I changed every 5K miles which that migrated to my 6.7L. Over time I learned to rely on the oil monitor. I run Rotella T6 5w40 all year long. Had my doubts for summer and contemplated switching to 15w/40 but oil analysis showed the 5w performed very well in summer after 4200 miles worth of towin 14K lbs up 8-12% grades against 105F air temp.

 

That is the point. I figure if I run synthetic and the computer prompts based on dino, I'm still way in the good.

 

I read somewhere (don't recall where) a very bad review of the oil testing labs. Basically a set of samples were drawn at the same time from the same engine and mailed in from different addresses. The results were all over the map, not even close to each other. Since I can't quote the source, caveat emptor, & do you own research.


With that said, I change oil every 6000 miles or so. I just get antsy and feel it is time for some fresh oil. I use Rotella T6 from 30k miles. Before that I used dino Motorcraft 10-30W diesel oil. Cannot tell the difference. Came to use Rotella T6 because I can get it for less than dino Motorcraft. Synthetic Motorcraft would seem like a monumental waste of money.


Oil changes, which I do myself, cost me $75 tops (60 oil, 10 filter, 5 fudge). Hope this helps. Dealer wants $150+ per change; thanks, but no thanks.

 

Ah, and one more detail on oil longevity of dino vs synthetic. In this engine, the longevity of oil is not the limiting factor; it is the fuel dilution that determines the end of useful life of oil.


Whereas in theoretical conditions a synthetic oil could perform its function for well over 10,000 miles, the reality is that oil gets sufficiently diluted with diesel fuel that you cannot and should not go 10,000 miles. You might read about bypass oil filtration systems, which are great, but do not help with fuel dilution.

 

I change at 5K. Good insurance to have fresh oil in there. I don't make oil or anything but I feel it is best.

 

I think it depends on how you use the truck, how many miles you drive each month.

For me, it's easy to use the OLM and do the 7,500 interval. I just do it when the truck wants it. Supposedly the control modules keep track of the way the motor is run and adjusts accordingly.

I also use T6. It's not expensive and covers all the temp ranges I operate in. The motorcraft blend is just too pricey for my taste.

If it takes you 6 months to run 7500 miles then I would consider going with 5k interval but technically, the truck would tell you to change the oil sooner anyway since it does keep track of things. Maybe just wait and see what happens? It might prompt you to change the oil at 6k? It won't hurt you to try.