Badger 2008-09-06 17:18:58
I searched these forums and can’t find a decent thread talking about
fuel mileage and reliability.
I want to buy a used(150,000miles or so)DIESEL pickup, mainly because
I’ve always wanted one, and secondly for the fuel mileage and engine
life span. I won’t be pulling a trailer, nor carry abnormally large
loads. I am a sales rep who is going to be driving a LOT more.
I am a big Ford fan but, I need a long lasting, good fuel mileage
Vehicle REGARDLESS of the brand. I hope I can get an OBJECTIVE opinion
from you guys.
Here is what I’ve come up with so far:
Dodge, worst mileage, best overall engine reliability.
Ford, better mileage, not as good reliability.
Chevy/GMC, best mileage, worst reliability.
These results are based on what I’ve read concerning 1983 and up
Keep in mind, I’m using brand generalities, not engine specifics. I’m
coming here to get opinions from you as to specific engine, axle,
combinations, and brands for my needs. PLEASE DON”T start arguments
with each other, I’m looking for ALL opinions and discussions.
FORD is my preference, but if Chevy is better for me, then Chevy it
is, or Dodge. All discussions are welcome, if TWO points are made,
your opinion of best mileage reliability, and best fuel economy. Keep
in mind, DIESEL info only.
PS. if you know of a site, which covers this in detail, I apologize in
advance and ask that you point me to it! Also, I have posted this on
other sites as well.
There are 10 kinds of people in the world:
Those who understand binary, and those who don’t.
Franko 2008-09-06 17:19:02
Try www.62-65-dieselpage.com for GM diesel info. They also have a
discussion forum with very helpful members.
98 Tahoe 6.5TD 4×4, 160k miles (22mpg highway/16 local)
86 Suburban 6.2 NA 2WD, 165k miles (26 mpg highway/18 local)
Jonathan race 2008-09-06 17:19:03
I’m going to chime in with my personal opinion, just so long as you
recognize that it’s just an opinion and not the gospel truth.
I think your list should read as follows, based on what experience I have
with my own trucks, trucks at work, and friend’s trucks.
For diesel pick-ups with 150K+ miles/7-10 yrs old:
Dodge (I-6 5.9L Cummins Turbo Diesel, Intercooled, direct injection): Best
motor, best mileage, poor automatic transmission, good manual tranny.
Ford (V-8 7.3L Powerstroke turbo diesel, intercooled, direct injection): OK
motor, worst mileage, poor automatic tranny, Unk manual tranny.
Chevy (V-8 6.5L turbo diesel, non-intercooled, indirect injection): Motor
OK but not powerful (better after ’97), middle of the road mileage, best
auto tranny, Unk manual tranny.
My friend still gets 23-24mpg on his 1989 Dodge with a manual tranny. I
used to get 20 mpg on my ’95 Chevy 6.5L turbo diesel with the automatic, and
trucks at work (when we used to use Fords) got 13-14mpg at best with the
I hated the Ford E4OD automatic transmissions, and I heard the Dodge
automatics weren’t much better. Funny how all the folks I know with Dodge
trucks of that generation all had sticks – something to do with the
automatic not being able to handle the torque of the Cummins 5.9L motor.
Chevy always had the best tranny’s but the 6.5L wasn’t the motor you wanted
if you wanted to pull, plus you had to really want to learn about them to
keep it running reliably (the Fuel Solenoid Driver was issue #1).
My preference based on the criteria you list would be one I didn’t even
list – a 3-4 year old Chevy or GMC 3/4-ton with the Duramax 6.6L turbo
diesel and the Allison 1000 tranny (I have a 2004). Good mileage (20-21),
good reliabilty, and a great transmission. Just make sure it has a 3.73:1
rear axle for the highway.
My two cents worth – Jonathan
Trey 2008-09-06 17:19:04
What year range are you looking for? what about price range? I have seen
reports of gues with the old 12V and 24V (pre1991-1998 range) Cummins Diesel
trucks getting 20+ MPG. A friend of mine had a ’99 Ford Excursion 4×4
Diesel, he got about 16 MPG. With the new Cummins 600, many have said the
fuel economy has gone down (mainly due to such high power output) if your
not pulling anything, and if you dont care about the noise, then then the
12v or older 24v would be great, (if the trans will keep up)
As for Chevy, a lot of guy I have talked to said dont get a pre-Duramax. The
Duramax was built in collaboration with Isuzu, (whom have been making
Diesels for many years) So the engine is pretty solid (even with aluminum
heads) and then the Alison trans is pretty much the way to go when it comes
to transmissions. I think the Duramax gets around 15-16 as well.
I have heard a lot of mixed reviews about the new Ford 6.6 Liter Diesel.
their old 7.4 was a pretty solid machine as I recal. just not the most fuel
friendly since its a 7.4, where the Duramax is 6.6 and the Cummins is 5.9.
So just in those terms, the Cummins has less displacement, and does not
consume as much fuel at any given RPM (if all three engines were mapped to
use the same amount of fuel per liter)
What speed will you be traveling at most? 5mph? 30, 60 85? If your sitting
in slow traffic, I would think the Cummins would be better since it would be
in a lower gear at a lower RPM. but if your traveling at 60-80, Chevy has a
five speed trans, where Dodge has four. So the Dodge my run at a higher RPM
at freeway speeds. The two trucks may be geared differently to accomodate
the difference in transmissions though.
If your doing a lot of empty driving, I would go with a 3.55 or higher rear
BTW, I am 01 few that do understand Binary.
Jonathan race 2008-09-06 17:19:05
Just for a clarification, the new Ford Powerstroke is a V-8 6.0L (not 6.6L)
turbo diesel with direct injection and an intercooler. The new tranny is
also a 5-speed similar to the Allison (but Allison is the King of the Hill).
The older 7.3L motors had only 2 valves per cylinder which is one reason why
they weren’t that efficient. The new 6.0’s use aluminum in their
construction similar to the Duramax, and use a variable vane turbo.
Chevy/GMC uses the Isuzu-designed Duramax V-8 6.6L turbo diesel with direct
injection, pilot injection, and an intercooler. The current Allison tranny
is a 5-speed, with a 6-speed automatic with selectable fully automatic or
manual shifting in 2006. This is currently the largest motor of the Big
Three. The latest version (LBY) uses a variable orifice turbocharger. I’ve
heard rumors that current 5-speed Allison’s are upgradeable to 6-speeds with
only a computer update, although they won’t have the selectable
automatic/manual shifting (6th gear being a double-overdrive).
All three manufacturers currently use 4-valves per cylinder, although most
were typically 2 valves per cylinder in the older models. Dodge made the
switch to 4-valves first, but although I have no concrete figures to go by I
can remember reading several folks writing that their mileage was pretty
poor for the first generation of 24-valve motors in comparison to the older
12-valve versions. I don’t really know why.
Cheers – Jonathan
Nosey 2008-09-06 17:19:06
Primedia has a brand new magazine out called “Diesel Power”. A friend of
mine has a copy of issue #1 that I recently read. It has a diesel truck
shootout in it and did a very good comparison on the Ford, Dodge, and GM
models available this year. You might want to check it out.
Badger 2008-09-06 17:19:12
I guess I should clarify too. I need to buy an older truck because of
price. 130-160000 miles or so.
Badger 2008-09-06 17:19:14
Thanks, I saw that. It seem to focus on newer vehicles though which
Badger 2008-09-06 17:19:16
Chevy has a
Well that makes 10 of us then.
I will be driving unloaded 95-99% of the time, and it will be mostly
highway. I really want a straight drive with a 3.4 or 3.55 ratio axle.
I put a deposit on a Chevy but the guy sold it out from under me. I’ll
keep my eye out for a Dodge.
Sarge 2008-09-06 17:42:24
Not sure about Ford Diesels but I driven both Chevy and Dodge diesels. We
use Chevy’s at work and they all have automatic transmissions. The latest
model is a 2002 and we get around 20 MPH on the highway. I drove the Dodge
trucks while playing porter for my wife who sells Dodge trucks. I picked up
and drove back to the dealership three in the last year. The best MPH came
from a 2004 Dodge 2500 Quad cab long wheel base with auto transmission. I
got 26 on the highway. This vehicle was brand new when picked up with only
3 miles on it. I had to drive it back from Tennessee to Louisiana so most
of the driving was interstate with the cruise control set at 70 MPH.
Trey 2008-09-06 17:42:32
I have heard many good things about the new ford engine, but also a lot of
bad things. Like the pilot injection not working correctly, and having to
reflash the ECU with a non pilot injection set up, causeing the new 6.9 to
be louder then the old 7.3 and even louder then the Cummins
Budroe 2008-09-06 17:42:41
That’s OK son, I’m can still use basic and remember most DOS commands.
Not even trying to understand Hex.
To those who have fought for it, Freedom
has a flavor the protected will ever know.
Anonymously scrawled on a bunker at
Khe Sahn, RVN.
Trey 2008-09-06 17:42:45
hex can be a little confusing..
That would be why I like the higher level languages like C++
Adding and subtracting in Binary is a real brain twister too!
Rich256 2008-09-06 17:42:51
Many, many eons ago I was a tech rep. teaching the digital computer to AF
technicians (It was the first airborne digital computer which was installed
in the F106). I made a rash statement that I could do anything in Binary
that they could do in Decimal. Some wise guy says “Yeah, lets see you do a
Square Root”. I put a rather simple binary number such as 49 (100011) on
the blackboard and even to my amazement I was able to do it. Just don’t ask
me to do it now.
R_d 2008-09-06 17:42:51
PI was a bad idea the injectors were not up to the quick computer
pulses…the intention was to make it sound like a gasser. Why? A diesel
should sound like a diesel…. The 6.0 does have a tinnier sound then the
7.3 but it is not a bad engine (I have owned a 7.3 and currently own a 6.0).
The 7.3 did have internal mechanical problems that developed once chipped.
The 6.0 hasn’t developed any problems although if you chip it you will start
eating head gaskets…
Jonathan race 2008-09-06 17:42:54
A diesel should sound like a diesel – yes, but a diesel shouldn’t also sound
obnoxious. There are noise standards as well as emission standards. I can
open the hood of my ’04 Duramax at idle and have a conversation in a normal
tone of voice while standing next to it. My friend’s Cummins powered Dodge
requires you to nearly scream at each other in order to be heard with the
Just an observation, but It seems like you are contradicting yourself by
saying the 6.0L Ford has inadequate injectors and then go on to say it
doesn’t have any problems. I never did have any serious problems with the
7.3L Powerstroke motors at work, although it did seem that the performance
fell off faster over the years than comparable Cummins powered units. It
was the Ford tranny that was a nightmare, but I understand they don’t use
the E4OD behind a diesel any more (and with good reason).
Cheers – Jonathan
Rich256 2008-09-06 18:05:03
Aren’t both the Cummins and International engines now using rail injection?
I was thinking they went that way to compete with the Durmax performance.
With my Durmax my wife’s only comment has been “It sounds like the wind
blowing” as the turbo winds down.
Frank 2008-09-06 18:05:10
Being able to have a conversation while standing next to an open hood (while the
engine is running) isn’t on my list of requirements for a diesel, or any other
type of engine for that matter.
Jonathan race 2008-09-06 18:05:12
Allow me to expand on my point. One of the reasons why some activities
(such as motorcycles, ATV’s, air boats, high-end sound systems, etc.) get
such a bad reputation is because of the noise. If other people couldn’t
hear what you’re doing, or at least if when they could hear it they weren’t
bothered by it, then that would be just one less thing for them to complain
about. Personally, I like not bothering my neighbors early in the morning
when I’m motoring out of my neighborhood.
I had an engineering professor way back when who continually claimed that
noisy motors were less efficitient. It takes power to generate noise, and
an engine that produced less noise due to primary design (as compared to one
that spent more energy to dampen the noise) was ultimately more efficient.
Cheers – Jonathan
Jay 2008-09-06 18:05:13
If you plan on working on it your self I’d look for a pre-98 Dodge. The old
12 valve is a breeze to work on.
Slap 2008-09-06 18:05:14
That’s because your parents didn’t bring you up properly. You have no
respect for your neighbours or any other people on the road. Heck you
probably get a woody just listening to the noise that truck of yours
makes… and it is noise. A Porsche, now that is a powerful sound.
Another problem is you will probably bring your kids up thinking it’s OK.
Tbone 2008-09-06 18:05:24
Unless you live in the middle on nowhere it should be.
If at first you don’t succeed, you’re not cut out for skydiving
Badger 2008-09-06 18:05:36
Thanks for that piece. I had not considered that.
R_d 2008-09-06 18:39:16
I was talking more about bottom end problems. Injectors seem to be a
common problem in both the 7.3 and 6.0. The injectors need to pulse too
fast to do the pre-shot and then the main shot so they would stumble and you
would get something similar to bucking… They dropped the pilot injection
and will reintroduce it in the 07 model year with much faster computers and
maybe twin turbos but now the noise from Detroit is they may just stick with
the single. Interestingly enough there are quite a few who still have the
PI and have had no problems so it does really appear it was a hit or miss
issue. I guess the sound level issue is a personal choice. I come from the
days where you wanted to hear and feel the engine running but now a days
some want everything silent. I’ll take it loud and clanky, if you want to
talk to me speak up. The E4OD was dropped a few years back in favor for the
4R100 which was dropped for the 5R110. I haven’t had the E4OD but I had a
4R100 that went out a 7k miles…the current truck has the 5R110 which is
not to bad but they are going through a major recall the will end up
covering everything made in 04 and 05…so once fixed I have hopes it will
be a good trans. The injection fuel supply systems on most internationals
are similar to what the old 2-stroke Detroit’s used but with higher fuel
pressures and instead of being cam actuated they are electric/hydraulic
(answer somebody else’s post).
Mcizek 2008-09-06 21:14:11
If I want to stop my truck and get out to have a conversation, which apparently
you guys do every day (maybe you should explain your line of work where that’s
needed), I’ll shut it off.
Mcizek 2008-09-06 21:14:11
LOL. Brilliant analysis.
The question is, how often does this scenario present itself to you, where you
are standing next to your running truck with the hood up while carrying on a
conversation in your driveway at three in the morning with your drunk cousin
that happens to also be your wife? Too often, apparently.
No, they’ll have enough sense to shut it off. They won’t marry their
Rudy 2008-09-06 21:14:25
Good idea, I was moose hunting and saw a big bull crossing the road about
300 yards ahead..
Stopped the truck, threw it in “park” got out and leaned across the hood to
sight thru my scope, and..
the truck was shaking so much, I couldn’t see thru the scope..
Had to reach back into the cab and shut off the engine..figured he’d be long
gone by the time I finished that “dance”
Nope, he was still there: BANG ! Got ‘im !
Tbone 2008-09-06 22:26:17
That is not the point although with your replies, I can see that you just
don’t get it. If your truck is so loud that you cannot talk to someone else
with it running (what a POS), then your neighbors must really love you when
you crank up that shitbox in the morning but then again, I suspect that you
really don’t give a c***.
If at first you don’t succeed, you’re not cut out for skydiving
Frank 2008-09-06 22:26:29
LOL. Why do I bother…you callin’ a Cummins c***?
It’s mighty nice of you, being such a wise and all-knowing person, to
spend so much of your time trying to straighten folks out on the net.