10w30 diesel oil in a 7.3, what can you tell me?

[hansj3]

Oh boy I found another rabbit hole. 2002 Ford e-450, 7.3.

There was somebody on here that made a confirmed 5% increase in fuel economy, just by switching from motorcraft 15w40 to motorcraft 10w30 diesel oil.

Convention has always taught me that the 7.3 takes 15W40, but I don't have a owner's manual to confirm that.
It's in an ambulance chassis, but it doesn't have a hitch so it's not towing, and I live in the upper Midwest, so days above 90° are somewhat rare. Days below zero on the other hand...

Would a modern Diesel rated 10w30 be acceptable for this platform? Easier starting and better fuel economy sure sounds nice

 

[kschachn]

There was somebody on here that made a confirmed 5% increase in fuel economy, just by switching from motorcraft 15w40 to motorcraft 10w30 diesel oil.

No they didn’t. Physics matters as does the ability to properly measure fuel economy changes due to an isolated variable. Both of which are lacking if someone claimed that.

 

[Donald]

What is wrong with a 15W40 or 5W40 diesel rated oil.

 

[MacManus99]

Run 5w40 diesel oil and sleep well at night

 

[hansj3]

No they didn’t. Physics matters as does the ability to properly measure fuel economy changes due to an isolated variable. Both of which are lacking if someone claimed that.

7.3l Powerstroke UOA Delo XLE 10w30

Here's my latest UOA AT 5600 miles. What does everyone think about the results? I'm no expert, but it looks like I can comfortably extend this oil out farther I have had the next fill in for about 4000 miles so far. Would 7500 be pushing it? The first two analyses were Delo 15w40, and it looks...

bobistheoilguy.com

Sample size of one, and I can't find his oil analysis... But everyone on the thread seemed positive about it

 

[kschachn]

7.3l Powerstroke UOA Delo XLE 10w30

Here's my latest UOA AT 5600 miles. What does everyone think about the results? I'm no expert, but it looks like I can comfortably extend this oil out farther I have had the next fill in for about 4000 miles so far. Would 7500 be pushing it? The first two analyses were Delo 15w40, and it looks...

bobistheoilguy.com

Sample size of one, and I can't find his oil analysis... But everyone on the thread seemed positive about it

Considering that gasoline even at the same gas station varies in energy density by up to 4% no one is able to make such a determination. Diesel fuel also varies by refinery and blending, and by winter/summer changes. There are myriads of variables that influence fuel economy in everyday driving and measuring it is just the easiest part. Ascribing an observed change to one isolated variable is key and is the much more difficult part. That guy had no clue what he was doing. He may have measured or charted a change but he has no idea why.

It's a prevalent misconception on Bitog.

 

[BituminousCoal]

Stay with a 4+ hths 0w40, 5w40 or 15w40 for your 7.3 powerstroke.

 

[Roadrunner01]

While I cant prove any fuel consumption differences, I have been running a 10W-30 HDEO for years in my 6.7 PowerStroke, my previous 6.0 PowerStroke, my 89 7.3 PowerStroke IDI, along with my ‘49 flathead.

You won’t have any issue with a 10W-30 in a 7.3 as the HPOP system will operate a bit easier when cold with the lighter oil. Cat developed this system along with International and specced 10W-30 in their engines due to the 15W-40 being a bit too vicious.

 

[Langanobob]

I’ve been running LE 10W30 conventional oil in my ‘96 PSD for the last 7500 miles. I have not noticed a fuel mileage increase, but with Mobil1 and Rotella T6 5W40 I used to have to add several quarts of oil every couple of thousand miles. I have no logical explanation but the LE 10W30 has completely stopped any noticeable oil consumption. I had an oil analysis done by Cat at 6,000 miles and viscosity and wear was OK. They said no need to change at 6,000 miles so I’m pushing it out a couple thousand more miles. Not having to add oil between changes makes the expensive LE 10W30 almost free in comparison to the previous oils.

 

[ofelas]

Hi,

"LE" ?

 

[Lyman]

Delo 400 LE SAE 10W-30 Demonstrates Fuel Economy Improvements

Chevron’s Delo brand of technologically advanced engine oils, lubricants and coolants, today announced that after extensive laboratory and field testing in heavy-duty engines, its Delo 400 LE SAE...

www.machinerylubrication.com

 

[BeerCan]

Hi,

"LE" ?

Could be lubrication engineers. They have a good reputation

 

[Langanobob]

It’s Lubrication Engineers, I should have been more clear.

 

[Greasymechtech]

Use any oil from the list in any grade allowed in your owners manual that matches your weather
Oil list and reading statement here:

FCSD Chemicals and Lubricants

 

[bullwinkle]

Firstly, Delo 400 LE means “Low Emission”, and any HEUI diesel will shear a 5W40 or even a 15W40 down to a 30 weight fairly quickly anyway, so why not start with a quality 10W30 and pick up some small MPG savings? Rosella T4, T5, and Delo 400 LE are all good examples, save money over a 5W40. (Sorry, didn’t realize the “LE” was not the Delo guy.)

 

[SteveG4]

Interesting. I don't remember having to top-off Delo 15W-40 fills in my previous '87 F-250 with an International 6.9L engine.

Perhaps it's because the injector systems on the International 6.9 and 7.3 IDI's was kept around 2000 psi. It appears the follow-on PowerStroke engines increased injector pressures by a minimum of 10x.

 

[madeej11]

Firstly, Delo 400 LE means “Low Emission”, and any HEUI diesel will shear a 5W40 or even a 15W40 down to a 30 weight fairly quickly anyway, so why not start with a quality 10W30 and pick up some small MPG savings? Rosella T4, T5, and Delo 400 LE are all good examples, save money over a 5W40. (Sorry, didn’t realize the “LE” was not the Delo guy.)

Yeah, I picked up on it when he mentioned the "expensive LE". Lubrication Engineers engine oil will be a lot more costly than Delo LE.

 

[jeepman3071]

Rotella T6 5w40 synthetic or Valvoline Premium Blue 15w40/5w40 are a perfect match for the 7.3L. I'd just run that and a good filter.

 

[Snagglefoot]

Here is the info from a 2002 Ford F-250 with the 7.3. I'm thinking basically they were recommending 10W30 for winter conditions, recommending 5w30 and 0W30 as it got colder, and 15W40 for the summer. That was 19 years ago. You can probably go with a 5W40 and cover off a larger range of temperature if you want. The category descriptions are pretty much obsolete.

 

[Zee09]

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