I only have 250 miles on new truck. I will use truck solely for towing 5er. The diesel engine guide states 5W-40 for severe use(towing over 1,000 miles or near max tow ratings). I've used Rotella T 15W-40 for years in last Ford diesel. The 15W-40 looks OK for my temps. Does anyone even make a 5W-40 that is a dino oil? Have never used synthetic. I don't know if it's good or bad, I just have no experience with it. I'd like to use Rotella 15W-40 as I have a lot of it on hand. I don't use the truck in cold weather at all. It sits in garage all winter. Anyhow, just thinking out loud. I hate to change what I've used for years, unless I really have to. I'd appreciate you guys advice... Sure don't want to start an oil war...

 

Nope.

Only synthetic. Rotella T6 is available in 5w-40.

Also Valvoline, and many other major brands.

Stick with a major brand, I think Ford Motorcraft has it too.

If you are near enough to Canada, get Petrocanada Duron-E, it is one of the best oils on the market.

 

Yeah, I looked some and didn't find dino 5W-40. I'm about to talk myself into what I've used for years Rotella T 15W-40. Subject open to discussion and input though....I've never let my previous trucks go over 5,000 miles before oil change. I don't drive a lot of miles a year, less than 10,000 so don't have to change very often..

 

The new truck will tell you when oil needs to be changed.

Just watch that fella appear on the display screen bearing stone tablets and follow them religiously.

 

15-40 is the only oil i have ever used and changed at 3,000 miles religiously. Open to others if it's better. Haven't found one but will check into it when I get mine!

 

Hi Jim,

As gearloose said, the truck will tell you when to change the oil. Mine has 5,500 on the oil and I have no plans to change it until the truck tells me to. Which should be in another 2,000 miles or so.

Also, you will have no problems with Rotella 15w40. This was the oil I was planning on using for my '08 6.4L truck until it was killed in an accident. I used 5w40 for winter service and 15w40 for summer.

Gearloose is also correct in saying that you will not find a dino 5w40. They don't exist, as a dino oil would require too much viscosity improvers to make the 5w base oil a 40w when warm. Such a large amount of viscosity improvers would make the oil shear down very fast, so after a few thousand miles you'd be closer to a 5w20, which wouldn't do well in high temperatures.

For my use I'm using only 10w30. It's the recommended grade and I'll see better fuel economy than if I used a thicker 15w40, as there will be less pumping losses in the engine.

Wow. That's some serious OVERKILL!

 

For years I have changed oil in my cars at 3500 miles. Mostly because I don't put many miles on any vehicle I own very fast. Kinda go with time as much as miles. And, I admit my diesel mechanic is right I am **** about my vehicles. After 63 years I don't suppose that is going to change. I do let the truck go closer to 5,000 miles when we are driving it while in California. Otherwise I change more often. Anyhow, back to the subject: All of my truck miles will be towing miles, otherwise I have other trucks and it never gets out of the garage. I see the 15W-40 is OK to use but shows low end of range at 20 degrees. I won't be operating the truck in colder temps than that. I guess it's easy to make an argument for the Rotella T 15W-40 since I have quite a quantity of it on hand. BUT, if that is a poor choice or the 5W-40 is substantially better choice I'll use it instead of putting the engine's health at risk. I could always find someone to buy the Rotella T around here as it is THE oil all the farmers use(almost the only). It's great to hear from the rest of you guys and get a feeling of your thoughts. Thanks to all. Great discussions.

 

 

Remember that each of these grades we are talking about are recommended for the 6.7L engine. I just went through the diesel supplement again, and it does say to use 5w40 for "severe duty". But the supplement does not define what severe duty is.

Towing, off-road, dusty conditions, and all others are referred to as "special operating conditions" instead of "severe duty".

Also, when you take the truck to the dealer for an oil change they will put in 10w30 or 15w40 without asking you what your usage is. Because of that I don't see any warranty issues with either oil, as I even had to call to find out exactly what oil they put in my engine; it wasn't on the invoice!

If you like 15w40, use it with no worries.

Trust me, I went through the same thing!

The differences between 15w40 and 5w40 are going to be negligible at best in warm weather, as these oils perform nearly identically when up to temperature. The big difference is going to be when it's cold out, as the 5w base oil will pump easier than the 15w. Once up to temp they both thicken to a ~40w. There are minor viscosity differences at temp, but they are small enough to not make a meaningful difference.

I would run a 10w30 though. It's certified to protect the engine, and is the recommended weight. Two months ago we did this:

https://www.ford-trucks.com/forums/1...ml#post9765199

Which involved me towing my trailer 1,800 miles on the highway as well as flogging the truck up and down a ~19% hill repeatedly. Oil temps got as high as 225° and the truck never missed a beat. With 10w30 oil.

 

We have been through a long cold winter up here in Michigan. The dealer has changed my oil twice now. They used the Motorcraft 10w30 diesel oil. It has worked great and starts at -5 F without plugging in the block heater have been normal.

I used both the 15/45 Motorcraft and the Rotella 15/45 in my 6.0 with equal results. I tried one service interval with Rotella 5/40 Synthetic and did not see a noticeable difference.

Regards

 

It seems to be called "special" conditions now.
Even with "special" Ford claims 7,500 mile (or 300 hrs) oil changes.

On EDIT: I guess that could just be for "off road" conditions but it was still under this special note in the attachment.

 

Thanks Tom. I guess I misstated "severe duty" and "special operating conditions", not sure there is a difference maybe just sematics. Somehow I'm just not crazy about synthetics or blends. Wish I could articulate why, just a personal dislike I can't qualify. I am a little concerned about the 10W-30 being a little too thin. When we cross the desert thru Arizona and California the temperatures can be 115 degrees. Barstow to Bakersfield thru the Mojave desert is an oven!!! My 04 diesel stayed well within temperature though it was one of the few times I heard the engine cooling cycling on and off. The 5er is 10,500 empty. In those circumstances I feel more comfortable with the 15W-40, but maybe the 6.7 is a different situation altogether. It's hard to get old ideas out of your head and it gets worse as you get older. Hence why I'm asking for other people's thoughts. Thanks for your replies, alway informative!!!

 

I ran Amsoil synthetic in my 06 Duramax and had real good luck with it ,a little pricey but great oil, i would run 10k between oil changes,seems like alot but Amsoil said no problem,if you have oil life monitering system the dealers tell you to go by that, the only thing i have been told is not to run synthetic untill you have at least 25k on your engine, you may also have a slight drop in oil pressure when you run synthetic, havent switched over in the new Ford yet as i only have 8k miles on it.Good luck

 

Hey Rick, good hearing from you. I don't let anyone do oil changes but me. I don't mind doing it, and always gives me a chance to get under the truck, and check everything out. May get too old to do it sometime, but not yet. Very picky about drain plug, filter tightening and just prefer to do it myself. Like I said the dealer's diesel mechanic says I'm **** about my truck. He knows I'm very very picky. I did have him put a new serpentine belt on my 04, said he never say an engine that clean. Old ways die hard, just the way I take care of my vehicles. Is the Motorcraft 10W-30 dino oil? I just have no experience with anything other than Rotela but it's good to hear what you guys are using and why. I may be **** about service but I can change...maybe. Good to hear from all of you..

 

Ooookay. This post just answered everything!

I do not think 10w30 would cause any harm under those conditions, but a thicker, -40 wt oil would be a FAR better choice for towing in 115° weather. If you don't tow in cold weather you will have no benefit with 5w40 synthetic.

Your current stock 15w40 Rotella seems like the ticket for your use.

I believe this is a myth and nothing more.

From Myths About Synthetic Motor Oils

If full synthetic would cause problems with break-in, you would find NO manufacturers who would use it as factory fill. My wife's brand new 2011 Toyota Sienna requires full-synthetic 0w30 oil. It seems to have broken in fine; it will never see dino oil.