Home Forums Gear Hunting Trucks and Four-Wheel Drives F250 Diesel Engine MPG question

What kind of mileage can I expect with a new F250 TD on the Highway?

What year?

Most of the 3/4 ton td's get +/- 20 mpg, after the engines are broken in.

It would be a 2009. Unless we can get a deal on a 2-3 year old truck

My '06 engine is different than the 2009---it's the 6.0---so I didn't answer you right away. But just for comparison and ballpark figures, I got 14mpg on the highway empty at 70mph from the day it was new until I got 26k on it, then it started getting better for some unknown reason, and now at 32k miles I'm getting 17mpg empty on the highway. Towing a trailer and grossing 13-14k I get 12mpg.
Not what I wanted; but that's what I get.
Oh, mine's got 3.73s and the automatic, and everything's stock. I've got plenty of power with the 3.73s and see no need to get the 4.10s.

BB,

I know one guy that has the new smaller diesel(2008) and he says he is getting maybe 17 on the highway. A friend has the bigger diesel and thinking it is the 2000 model and he gets 21 on the hwy.

really hard to get that great mileage these day even with the trusty old 7.3 because of the new crappy ultra low sulf fuel.

they're all gonna drop off of there sweet spot when running above 1800rpm (IME)

can i get 20 with my 6.0? sure... but on my normal short work commute with like 5 stops & accelerations back up to speed each way I get around 16.

i've heard many reports that the new engine while jacked with tons of power, doesn't do as well on fuel.

I've got a 2003 f250 with the 6.0 liter and have never got better than 16 mpg on the highway at 70 mph or less, while consciously TRYING to get good mileage (light on the throttle, etc.). My truck is stock EXCEPT for 315-75-16 BFG All Terrain tires (about 33-34" tall). It has 132k on it now and thats the best I can expect...16 mpg. We all know that us guys lie about three things...well maybe more, but here are three:
1. Group size
2. The fish that got away
3. Fuel mileage

I've gotten 20 & change but i don't get that normally.
It's rare that I can run out a tank of gas with out a bunch of stop & go, shut down, cool off, warn up etc on the same tank.

But if I can get a chance to run out a tank on hwy speeds with minimal stops or slow downs it'll do an honest 20+

but, normally with 20 or more cold starts per tank & my short stop & go driving I get 16 like you said with my 6.0

I think mine's an 05, cant remember right now.

I been looking real hard at the new trucks, got a 2006 Ford Superduty with V-10 (gas) & .373 gears, 4-wheel F-350. It gets 12.5mpg (used to get 15mpg before changes like tires and fuel boost with Bully Dog) on the highway at 70mph empty with 285 tires. Pulling heavy it goes down to 9 mpg!

Those new Ford diesels seem to range around the 14 to 15 mpg empty driving 70 on the interstate hwy. Towing I am told by friends who have them, that they get 12.5 to 13 mpg pulling 8,000 to 10,000 lbs. They only have around 12,000 miles or so on their new 2009 diesel trucks. Same goes for those larger engine Dodges with the Cummins in them.

Those 7.3 diesel Ford trucks used to get 20 mpg empty and pulling was in the 16mpg area. The 5.9 Cummins in the older Dodges got 21 to 23 empty on the interstate hwy and pulling dropped down to 18 or 17 mpg. However, that was before the new fuel and the tech changes on those diesels engines.

550 mile round trip last Sunday, A/C on and 8 mph (cruise control) over the 70 mph limit got me 19.9 mpg. Hand calculated (Trip comp read 20.3) in my 2003 Cummins. I don't believe the new new ones do that well, regardless of the brand.

Horsepower keeps going up, emissions standards get tighter, new fuel injection systems, new cleaner-burning fuel; I guess as a whole we're heading in the right direction, but I'd accept these emissions-based changes and go from 300+ horsepower back to 200hp if I could get mpg in the low to mid 20s. My trucks with less hp still had plenty of power for what I do, and I disagree with the trend toward more power and worse mileage.
Too, a lower hp version of what is built now would last forever. Look at the 6.0 Ford; it's fine as long as you don't boost the output, but if you do, it shortens the life more than I think it should. It stretches headbolts for crying out loud. It has faulty EGR coolers---who's the genius that designed that? Look at the trouble they had with its injectors.
I'm disappointed in the progress made in pickup diesel engines over the last 15 years, and I think it's revealing that the manufacturers blame the government and fuel. I believe a diesel pickup has the potential to be the best thing to ever come from the small truck builders or I wouldn't be so disappointed. Thats why I'll look at Japanese made diesel pickups, if they ever come out with one that fills my needs...screw these companies that can't build a reliable, efficient product, and go bankrupt while wondering what happened.

On my 06 5.9 cummins I got ~21 on a long road trip running about 70mph. But it did take nearly 40k miles to get the engine truly broken in (I hadn't worked it hard enough) and when new I was getting 17 and change on the freeway. That's hand calced mileage.

That's why I've been kicking my butt for buying the Ford. In '06 I wanted to get another Dodge because I had liked my '97 so much, but the Dodge salesman was a disinterested know-nothing. I told the wife I wasn't going to give that sob any of my money and we went across the street and got a Ford. I sure showed him!

In fairness though, I've had absolutely no trouble with the Ford...since it got out of warranty.

Don't get me started on our dealership. Suffice to say, I won't even buy a valve stem cap from them, or trust them to fill up the windshield washer tank. How many trips to the dealership, over how many months and how many days in the shop do you think it would take to find a broken hoseclamp? They really went out of their way to make sure they'd never get anymore business from me.

The new Ford 6.4's have bad reputation fuel economy wise, they're not getting nearly the fuel economy of the older diesels. I wouldn't expect more than about 14 out of it on the highway. Go to www.thedieselstop.com and browse their forums, they're a ford diesel specific forum. Fuel mileage is down across the board with all brands since the new emissions equipment has been required, but dodge and GM haven't dropped nearly as much as Ford. Ford's replacing their 6.4 diesel next year so things will probably change. The mileage drop isn't due to the new ULSD fuel as many claim, I've got a 98 dodge/cummins and all the available fuel around my area has been ULSD for a couple of years. I've had no mileage drop, it still gets 21-22 mpg on the highway.

Ford is going to replace the 6.4 already? I hadn't heard that. Wow...that's about as impressive a lifespan as the 6.0, as in not very impressive.

Ford is severing ties with Navistar who produced the 6.4 and the 6.0h No! They also made the 7.3, but their major heartburn began with the 6.0. Ford has decided to make their own diesel that is coming out as a 6.7 with nearly big hp/tq numbers if the rumors are correct.

I'd like to see them use something like the old, old Cat dozers had...heavy, overbuilt and lots of low-rpm torque.

Now based on what I have read on this thread that is very welcome news.

I have a 2008 F350 King Ranch, with the 3.73 gears. Highway and around town average near 15. Pulling an 18,000 lb fifth wheel, she runs 12.
Last Truck was a 2004 F350 6 liter. She averaged a tad over 18 empty, and 12 towing.
Mileage in the new trucks is down due to the required diesel particulate filter (D.P.F.).
About once per tank it goes into regenerative mode, where it injects diesel into the filter and lights it to burn off the trapped soot.
While there were many issues with the 6.0, especially the early ones, I never had a lick of trouble.
There are very few problems reported with the new 6.4, except marginal mileage. The 6.4, by all accounts is a good engine.

What mcmurphrjk said. When Ford went to the 6.4L they also had to include additional emissions equipment and mileage is down. Ford now has 3.55 gears available in the diesels to help with mileage, and going forward (2010 model year) they no longer offer 3.73 gears in a single rear wheel (SRW) truck. You now have 3.31 and 3.55 gears available in hopes of increasing mileage still. Obviously as rear wheel torque is a function of gearing you lose a little torque due to the higher gears (numerically lower) but will maybe squeak out a mpg or two better than previous years. If you go to the diesel forum on ford-trucks.com you'll get a good idea of mileage in the new Ford diesel trucks. By the way, the F250 and F350 are the same engine and drivetrain, so don't let that sway you.

There were some surprised and pissed off people when the 6.4L came out and the new emissions requirements had to be met. The mileage was much less than some people thought and it appears Ford was listening and that is why they are trying to use higher gearing to get a little better mileage.

Good news. My '97 Dodge diesel with a 5sp and 3.55s never hurt for power. I'd gladly run 3.31s in the '06 Ford I've got now, if Ford would build it that way so everything coordinated.

Run a taller tire to get an effective gear ratio that is lower numerically.

They've got me believing it's not that simple anymore, and I don't understand why it wouldn't be. From what I gather, if I put 2" taller tires on my F-250, mileage will go down.

What mileage do you get with it now? My 2003 f250 gets 16 mpg on the highway. It has 315-75-16 tires on it which are supposed to be 35", although they are more like 33".

As far as the USLD, it doesn't seem to be influencing mileage in the summer, but the Winter diesel costs me 15% in fuel economy in the Semi. I hate the stuff.

FWIW, I was delivering to a customer the other day with my '97 F250 (which still gets 18-19 MPG with 280,000 miles on the clock), and the customer was complaining about his 08 only getting 10 mpg. He wanted his '98 back.

As an aside, how can it be good for the environment to burn 50-80% more fuel? A country bumpkin wants to know.... JMO, Dutch.

My 97 Cummins with the 3.55s does well as I can get 20 mpg pretty easy if I keep my foot out of the pump. The 2010 emissions will be a bugger. They are talking urea tanks on our dump trucks. I have not heard of too many good reports as far as fuel economy goes with the DPF trucks. My dad's 6.0 can average close to 20 if you keep it 60-65. He has the 6 sp. manual. My brother is in the process of putting a 1995 Cummins in his 1995 F350 4x4. He is going to use a Superduty 6 sp. manual and transfer case. Economy should be similar to my Dodge as he has the 3.55 gears.

I have 91 DODGE 3/4 TON 4X4 WITH 12VALVE 5.9 CUMMINS .It has 200K+ and gets 17-25mpg the only thing I do is add 1 QT of SEA30 oil in with the fuel on every fill up and plug her in when it gets cold.

Moving up to 35" tires is virtually guaranteed to cut your fuel mileage,unless you have a 4.10 axle ratio.

What are your thoughts on this then: I am mounting up some 37x12.50x16.5 Goodyear Hummer radials on my 2003 F250 diesel (6.0), due to the fact that a gent nearby sells the military surplus version of these tires (95% tread) for $100 each. This beats the heck out of the BFG All Terrain 315-75-16s that cost me about $210 each that I have been running. (As an aside, I laugh everytime I see people with the large offroad tires that are 20" or larger rims, as these tires usually are $400+ EACH!!! :o). I have 3.73s now, and with the 315 tires have NEVER ever gotten better than 16 mpg empty. I am also installing 4.30 gears, this should bring back the RPMs into the "sweet spot" hopefully. Now I am curious what I will get for mileage.

Seems like you'll have to go through an aweful lot of those discount tires to pay for the gear swap.

That would be true had I not gotten the rear end gears for free from a friend who swapped out his gears, the same friend who will be installing them for me (again for free). Just have to buy the fron gears ($250 or so) and have the same friend install. One set of these milsurp Goodyear tires will more than pay for what I will spend swapping gears!

That changes the equation Sounds like a good deal.

plus all the wicked clearance you'll gain.

did you have to get a set of 16.5" wheels?

Yes, I found a used set of Weld Racing "Mountain Crushers" 9.75" wide for $240 with 37" tires that had only about 25% tread left. Sold the tires only for $150, so I have "net" $90 in 4 rims that sold for $350 each new!! God, I love craigslist!

sweet!

My 7.3 still gets 20+ mpg with my special fuel mix. Every fill-up with that cheap watered down junk is mixed with 12 ounces of ATF. Boosts the fuel mileage right back up to where it used to be before the junky fuel came along.

Any of you guys tried mixing Marvel Mystery Oil to the new diesel? My mechanic said to try it. But I have reservations about damage in my '99 7.3

I doubt Marvel Mystery Oil will do any harm to your 7.3.

One of the mechanic here has been running his truck on used ATF for the past several years. Not something I would do but he gets the ATF for free.

OK. But will it do any good, then?.....

No it will not. The fuel additive specifically for diesels is Lucas.

http://www.lucasoil.com/products/display_products.sd?iid=26&catid=2&loc=show

Buy it by the gallon and RTFI.

The guys on "Trucks" (a TV show) are putting an old Ford crew cab body on (I think) an 05' Dodge chassis. That will be the best "power poke" around. LOL.

I'm on my second 7.3 Excursion- the first consistenly got 20 mpg on the highway as long as I kept it at or below 2K revs. It would tow @13-14, 28' twin-engine boat. Bought it new, stock tires, sold after job loss in '04.
The '02 I have currently have has slightly larger tires (285's) that cost about 2 mpg. I haven't been able to get any better than 18 out of this one, 12 towing. Big tires cost $$$$, period. I'm going back to stock or skinnier or both when these big BFG's wear out.

I used to have access to free sump JetA, and burned it in both my Ford and Jetta TDI. Jet has had all of its lubricity removed, so I always put some lubricant back in; ashless 2-stroke always worked quite well, and is what I use now with the ULSD. Injectors are big $$$, so an additive (unless you have access to veggie diesel) is a good idea. ULSD has not appeared to cost me mpg. The killer on mpg is the winter blended fuel, with 2-2.5 less the norm.
If you're running a Ford, you could read for weeks on www.dieselstop.com on this topic.

it'll provide some lubrication for the injectors.

i'd think 2 stroke oil would be better.

I have run ATF &/or Marvel Mystery Oil in my 99 7.3 since it was new. It currently has 236K + and shows no signs of slowing down.

What does running ATF or Marvels do for you? I am curious...better fuel economy? Cleans injectors? What? Thanks.

I would assume cleaning would be the benny with some lube improvements but I'm curious too.

2-stroke oil mixed in netted pretty good results with no adverse effects. i personally run opti-lube xpd in every tank in my 05 cummins. it actually did raise my mpg 2ish. its like $42.00 a gallon and treats about 250 gallons, so over time it pays for itself by a bit, but also makes my engine run much better and quieter.

i wouldnt have believed it, but i actually witnessed it. i got back from korea and didnt think much about it and ran my truck for awhile and got to thinking why i wasnt getting the fuel mileage i normally get which is 22-23 hwy, then it clicked, i hadnt put any opti-lube in it since i ran out right before i left. so a week later i had it and 2 tanks later im back to my 22ish hwy and 18 city. granted thats being nice to it... that totally sounded like a sales pitch. lol, im not affiliated with them at all.

The tests were run by an independent company i guess. i read about it on cumminsforum.com if anyone wants to check it out. *fuel additive test*

oh, basically the fuel conditioners and what not add more "lube" to the fuel and some have detergents and such to clean out the fuel system and injectors. with the ULSD they take out a lot of the lubricating properties, which is why the older trucks dont like them at all. I.E. fuel pumps which use the diesel fuel to lube everything. this ulsd stuff just doesnt give it enough, which is why the 2-stroke did so well in the lubricity test, **but doesnt have any detergents for cleaning purposes**. oh, make sure you use the ashless. i dang near guarantee it will quiet your engines down, especially the 7.3 guys. generally 1oz to the gallon. give it a try boys & girls!

P.S. yes, it was all hand calculated and the trucks isnt totally stock...

Based on the tests done by Arlen Spicer, that is in Browningguy9's post above, I sure would NOT use Marvel in the diesel fuel. Spicer is a well known and widely regarded poster on "The Diesel Place" forums.

Take a look at the results chart on page 11, Don.

http://www.johnfjensen.com/Diesel_fuel_additive_test.pdf

yep, that's a good reference.

I had been using diesel kleen on occasion but I haven't been using anything lately.

Thinking I'll try the TC-W3 as it's been probably the most popular for many years & has proven itself even if it's unconventional.

my boss has a 7.3 with almost 300,000K on it on the open highway cruise set at 70 he has got all the way up to 32mpg. we got a superchips max tuner for it and cranked it all the way up. before that 20mpg was pretty normal, when he is pulling our skid steer he get 16-18mpg. we use schaeffer oil and also their fuel treatment.

I'm guessing the problem is with particulate and soot and it's a problem with newer rigs. It's not a problem with lubricity.

I guess I haven't had any problems personally, just an awareness of the lubricity issue with the new ULSD so I try to do the injectors a favor every now & then by "lubing up the fuel"



Bio D is actually number 1 on that chart I believe so our summer blend fuels up in my neck of the woods have got me covered.

But the bio fuels have bacteria issues so I'm sure to buy from filling stations that sell a LOT of fuel so I know I'm not getting anything that's ben around long enough to have to worry about the bacteria issues.

I guess I should probably be more worried about "dry" fuel in the winter months when it's too cold to blend the Bio.

I know a place almost as steep as that. I ran my '97 Dodge 130 miles at 50-55mph in 5th gear (most of the way)and by really filling it up at the start and not so full at the end, I got 25 once and 26mpg another time. Otherwise I got 20-21mpg on the flat.
I'M talking about going from I-90 out of Coeur D'Alene, south on hwy 3 clear into Lewiston.
We did the same test without the bountiful vs lesser fillups in our Civic and got 50 mpg.

well in his case it was across north dakota.

I have friends that have owned 7.3 Ford diesels ever since 1999 and they never got over 23-mpg period, not even when going down hill to Florida. I drove a 2001 7.3 F-250 diesel for almost 8 months and never got over 21 mpg empty savvy.

Now to say that a 7.3 is getting 32 miles per gallon is one BIG FISH STORY!!!

I don't believe thats possible at 70mph, speed being the enemy of any diesel engine, coupled with frontal area on a full size truck. Good to great mileage is achievable at lower speeds, however. I drove my '03 Cummins from my house north of Atlanta yesterday to Omaha, Ga, close to Lake Eufaula on the GA/Al state line. Slow going with the ice and fools on the road, I guess my average speed was about 50 mph. 402 mile round trip and 16.02 gallons of diesel = 25.1 mpg. (Unloaded)

pyro6999; I'm not calling you a bs'er here on the 32mpg thing...but whoever told this to you is, or doesn't know how to fill tanks and check mpg. There's a big difference between what someone else tells you and swears on a stack of bibles, and what you actually do and see yourself. What someone tells you isn't something you know, it's something you heard.
The fact is, (as I see it) from my experience of owning four different diesel pickups --- two Fords, a Chev and a Dodge --- the only way someone is going to get 32 mpg out of the truck as you described it is to do it with one heck of a tailwind, going down a steep grade for the whole test, or throwing in some other factor that we haven't been told about. Ain't gonna happen.
I like to ask guys about their trucks and sometimes some of the things I've been told by them about the power and the mileage of their trucks amounts to nothing more than a joke, but alot of them don't know enough about it to know when to stop exaggerating. This is especially true when someone is suffering from brand loyalty. Some of them don't know the difference between what they want and what they've got.
When it comes to figuring mpg, there's alot of guys who flunked math in school.

Check for "powerstrokehelp" on youtube. Guy specializes in nothing but powerstrokes. I've been watching a few of his vids - interesting really.

As to adding things to the fuel (particularly ATF for lubricity), when I worked at Peterbilt we specifically did NOT recommend doing this. Usually due to concerns over injector life and possible combustion point differences with diesel. ATF isn't designed to mix with diesel and can combust at different times(points) in the compression stroke. This came from CAT/Cummins who are in the business of selling parts to guys.

I currently work on the maintenance team for the largest trucking company in the world. We don't mix anything at all with our fuel for "added lubricity" - that's 14,000 trucks with 6 million miles a DAY put on them. If it made them last longer, better MPG, cheaper to maintain - we'd do it. Simple fact is we don't because there isn't a pay off.

Andrew,

Thank you for posting your experience. I am curious if there are any "tricks" that you do to your engines/drive lines that you could share.

We don't really do any tricks - a quality PM service is about it. We run Mobil synthetic with drains at 75,000 miles. Swap filters inbetween. That seems to be the bigger thing - RUN SYNTHETIC. Everything I've seen from where I am now to when I was at Peterbilt - synthetic is the way to go. I saw it in smaller fleets and now in the larger one.

Yes we have failures but combine it with the fact that across 14,000 trucks, we only have to pay a wet service on a unit every 9 months - what we burn down is easily paid for in the savings there. Plus getting a driver in for the service is easier to do when it isn't done every 4 weeks like you would on dino.

We do have a larger than normal fuel filter that Baldwin makes for us special. About 2x the size of normal. Fuel quality isn't the best across the entire country and buying a million gallons a day, you get some not so good stuff. Talking about sediments, not asphaltines or lubricity issues.

Our largest issues seem to be more along the lines of trans failures.

Although - the smaller line of business I work in (within the larger parent organization) is starting to look at rebuilding a portion of the fleet rather than replace. Like everyone they went heavy on the 06,07 years and they are all starting to hit that wall of larger failures/issues at the same time. Rather than replace all of them (we'd rather replace a smaller portion every year -say 20% of the fleet so you have a 5 year turn over) we are kicking the tires on what we'll do.

At the end of the day - we are a large company with several smaller fleets that make up the total. We can and do get to experiment on different things in different regions. We've not found anything that we could attribute to fuel issues that required anything additional to extend the service life, increase MPG (think what .25 better MPG would do for the bottom line across 6 million miles a day) or make our stuff last. We have the same failures, number of failures and severity of failures that we did before USLD.

Andrew,

Thank you for the detailed response. I service my vehicles myself on a regular basis and I use a lot of the same stuff you mention. If it is good enough for your fleet, it should be darn good enough for mine.

What are you running for powers?

We don't do anything that propriatary - what we use is what everyone uses - just that we get them cheaper

Andrew,

It varies from my daily drivers which are 2008 Toyota Sequoia, 2008 Camry Hybrid, 2006 Honda Accord 4 cylinder which I use Mobil 1 and Wix filters across the board. I also change the cabin filters at about 15,000 miles. It is amazing how dirty they get.

I use Shell Rotella dino 15w-40 and Fleetguard filters (oil and air) in my 2000 Dodge Cummins 2500, but I use Amsoil or Royal Purple in the transmission and differentials/transfer case. I have a 1997 Fleetwood Discovery motorhome with a 5.9 liter Cummins which I use Amsoil or Royal Purple in the engine, Transynd in the Allison, and Amsoil/Royal Purple in the differential.

My two stocker race cars (LT1 and a 396/325 hp) I use Wix Racing filters and Valvoline dino with Lucas Zinc additive. On head's up races I use Royal Purple Racing 0w-10 and only 4 quarts. Royal Purple in the Turbo 350 or Turbo 200 and Royal Purple in both 12 bolts.

Curious - why the dino in the engine and Amsoil in the drive train behind it? (Ram) and then Amsoil in the RV engine?

Curious is all as to why the spread on the styles of oil/fluids being used.

The RV will sit for longer periods of time, but it when it is being used it is under much more strain than my truck. I have always used synthetic in the RV and had excellent oil analysis results.

I bought my truck used about 5 years ago. It was more of a work in progress. The truck only had about 72,000 when I got it and I wanted to learn more about how to improve the performance of a diesel with different injector/turbo combos along with modifying the fueling curves.

The first thing I did was to replace the transmission and converter with one from Dave Goerend. I wanted to remove that variable from the equation. I also knew that I would be putting in head studs and changing out the camshaft.

All in all there would be several more oil and filter changes than normal for the time/mileage intervals due to modifications to the engine. I didn't think I would get the full advantage of the synthetic since I would be changing it so often until I got my final combo figured out. At that point I would probably switch to a synthetic and normal oil change intervals.

Funny thing has happened in the process. I have built more motor than the truck can safely handle. Not that the truck is dangerous to drive. It is very smooth and powerful while getting good mileage. The problem is that this combo should be in a long bed dually rather than a Quad Cab short bed single rear wheel truck.

I plan on selling the truck and buying a crew cab dually. I have my eye on a 2004 Ford F350 with the 6.0 and 5 speed automatic. I am aware of the problems of the 6.0, but this particular truck is owned by a friend of mine that has worked most all of the bugs out and takes incredible care of his vehicles. It has 66,000 miles on it and has a nice Transfer Flow tank in the back.

I will drive the truck as is for as long as it gives me good service. If the 6.0 ever gives up the ghost or gives me enough trouble, I will replace it with a very nice 1998 12 valve Cummins that I have sitting in my shop right now. Or I will sell that motor and put a later model Common Rail Cummins in it for the quieter engine.

I hope I answered your question in the prior post about my truck and why it appears unusual that I am using dino in front of synthetics. If you are asking about the various synthetics is more due to availability than anything with the Amsoil vs. Royal Purple. I prefer the Amsoil, but I have a better source for Royal Purple and it is much cheaper for me than Amsoil. I just use the Transynd in my Allison because of the extended drain intervals that Allison approves of with their "in house" product.

I have drifted more to Mobil 1 for the engine oil because I can get it so darn cheap when Wal Mart runs it on sale and it has been giving me the same good oil analysis results that I was getting from Amsoil/Royal Purple. If it has been as good then why spend the extra money. Amsoil, Royal Purple, and Transynd are the only synthetic transmission fluid I have available to me. I can say with certainty that the dino oils I had be using in my daily drivers didn't do as well with the oil analysis that I have been getting out of the Mobil 1, Amsoil, or Royal Purple.

Our dyno results have been surprisingly similar with Valvoline vs. the synthetics in the 5w-20 weights. We have seen the cars pick up about a tenth when we drop out a quart and use the 0w-10 Royal Purple for our heads up races. We have also found that we need to add Zinc to the Valvoline especially for the flat tappet motors. Not so much for the roller cam engines, but the racing synthetics come with the added Zinc in the first place.

Thanks for the explanation. Very interesting. I really appreciate it.

Oldelkhunter,

THANK YOU for starting this thread! Wife and I have been looking at a one size does all vehicle for me to replace my 2000 Ford Explorer and 89 F-250 Gas 460 4x4 p/u. I drive quite a few miles per month as evidenced by the 207,000 miles on the explorer.I must have 4 wheel drive and decent ground clearance to get to many of my mountainous area rural appointments. Add to the equation that I am a might bit bigger than the average joe at 6'3" and 245 lbs plus my absolute aversion to buying a Jap rig and one can see why a Subaru will not work for me. Also needing 4 doors as I almost always have a couple of huting buds along on my adventures. Hoping to buy one rig that will be my daily driver as well as hunting rig and pull the 29 foot camping and hunting trailer. Just read this entire thread as I was about to pull the trigger on a deal to trade in my Explorer and 89 PU on a 2004 F-350 4x4 with a 6.0 liter diesel.

NOW I am thinking of holding off and looking for a slightly older Ford with the 7.3L motor. Am I on the right track? Love the fuel mileage and power of the Dodge Diesels but cannot stomach the body style or that would be my direction. Any input here on the Chev Diesel Quad cab 4x4 P/U's? Is a 7.3L Ford Diesel lots better than the 6.0? Enough better that it is better to get the older and likely higher mileage rig? I am really hoping to get something that will be in the 20+MPG range over the highway, yet still do above requirements. Idea's and suggestions hereby solicited!

Ford made a great diesel engine in the 7.3 but if your in that rig a lot, best be wearing ear-plugs because it will, like the older Cummins diesel, cause you to loose some of your hearing.

The newer diesels are much quiter in that respect....thank GOD!
However, because of the low sulfur fuel, they don't get near the mileage either. In the beginning FORD did have some problems with their new diesel engine but most of that dust has settled down and I have not heard any great complaints about fire coming out the exhaust, like in the beginning.

Cummmins diesels in the 5.9 do get tops in mileage but you must like the rest of the truck or shop elsewhere I suppose. I view a truck like a tool! So body style doesn't way me a whole lot, it is performance and mileage etc. You just remember, you must be doing a whole lot of pulling and running that truck near 60 hours a week to justify the cost of that diesel engine.

My Ford E-350 Superduty gets used between 8 & 10 hours a week, so a diesel is not in my interests or benefit. I can pull 12,000 lbs with that V-10 gas engine and it is as quite as a church mouse on Monday morning. I now (since bigger tires installed) get 13mpg on the highway at 70 mph. I tow 12,000 and get 8.8 to 9.4 mpg. Average life of a V-10 is close to 180,000 miles before major overhaul. Many have gone over 200,000 plus. If you have a diesel truck, you best trade it off before it gets 80,000 miles on the vehicle or you will take a beating and most dealers will not touch one that has over 100,000 miles on the rig. If so they won't give you SQUAT for the truck. You don't have that problem with a gas engine truck!

The FORD 6.0 Diesel was a BUST as far as dependable diesel engines go, if your going to compare it to the 7.3 Ford or 5.9 Cummins engine. One of the reason FORD got on the stick and started all over again from scratch.

I have a very good friend that purchased a 2006 with the 6.0 engine and he has never been happy about his new truck. He would take a beating trying to retrade. So he took that truck to a fellow who is an expert on diesel engines and made some changes, starting with a new exhaust system and added the Bully Dog Box.

He pulls a 32ft trailer loaded with horses, dogs etc. down in the Ozark Mountains where hills are plentiful and steep, such as Hwy 65. He now has most of the Nit-Picking things solved but it cost him lots of heartache and money.

The Chevy diesel is a good one no doubt about that and the plus side is GM has it mounted in front of the best Tranny on the market in that Allison box. Never heard anything bad about the Allison hook up. I don't think you will get in the 20's with mileage but 17 to 18.5 seems the norm from those I know who run them around my area.

Between my dad and I we have had an 1987 (6.9 IDI), 1993 (7.3 IDI) '95 (PSD) and 2000 (PSD). They all got 16mpg +/- hwy. We always heard from everyone that we should be getting 20, but in reality never got close. I think its an internet rumor.

I've only owned the 7.3 in Excursions, one a 2000 model and the other the 02 I presently own. My driving habits with both being the same, 2000 rpm is a 'never exceed' rpm for economy's sake. I could consistently knock down 20 mpg on the highway with the 2000 model, hand computed, not what I saw on the overhead. The '02 I presently own has never achieved better than 18.1, and the loss is directly attributable to the fact that it has 285's on it in comparison to the stock 265's the 2000 had. As always, bigger rubber is a penalty.
Both trucks towed in the 12-14 mpg range depending on wind and terrain; 8000# twin-engine boat. Both trucks had the same fuel mods and ran the same Superchips programmer.
Jim

Not just to start an argument, but what you've said is not the same mpg as what alot more people have said they got...including me. Your figures sound like you limited yourself to 4.10 rearends and aren't telling us that. Maybe it's something else, but if I took your trucks and drove them, either I'd have gotten better mileage than you did, or there's a mechanical reason why, unless you have a knack for buying lemons, drive in a way that uses more fuel than most, or your trucks were set up to not be able to get the same mileage as I know they can get.
Your statement, taken at face value, is more like an internet rumor than it is a presentation of factors that would show why it is true...or not true. So, instead of just throwing out a blanket statement, why not tell us more about your trucks and how they were driven?
Or maybe "but in reality never got close" means you "only" got 19.9 mpg.

son-in-laws 99 F350 powerstroke gets 17mpg highway at best . local driving on township and county roads he gets 14mpg .
he doesn't have 4.10 rears


I've talked to many powerstroke owners that never see 20 mpg .

While I don't doubt what you are getting because the best I have now gotten with my '06 psd is 18+ mpg (empty, slow and 3.73s), there's a guy in this thread claiming 32mpg. What do we do now?
My older trucks of other manufacturers' got better mpg than my '06.
Alot of mileage differences boil down to terrain, speed, load, gears, air filters being clean, wind and honesty---plus the ability to accurately calculate mileage. These discussions will always be around, because of the apples-to-oranges tests.

I have an 01 4x4 F-250 with the 7.3 and 285's, Mobil 1 gear dope in both ends and Rotell T 5-40 synthetic in the motor. I also use a DP Tuner programer with the 80 hp 'econo tune' and the 60 hp 'tow tune', it's all push button so I can easily change from one to the other. I average 16-19 in town and on the road, the very best I've seen is 19.8 and that was ALL highway keeping it below 2000. The last time I filled up it calculated 18.1mpg. When pulling our toy hauler I usually average around 12 mpg. All milage is 'hand calculated' and NOT from the 'lie-o-meter' on the overhead, it usually shows 20-25...I only wish!!

Just read a review in one of the car mags, maybe MotorTrend and they were getting 15-18 mpg with the new Ford Super Duty. Better than the Dodge they were comparing with, FWIW