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I am looking at buying a used Duramax, questions.

Discussion in 'GM Diesel & DuraMax' started by giorge, Feb 27, 2011.

  1. giorge

    giorge New Member 100 Posts

    I am looking at buying a 2002 GMC Duramax 3500 DRW 4x4 crew cab with 65k miles on it.

    My first question is what is the MPG for a dually compared to a 2500 crew cab 4x4?
    2nd is a 2002 a good year to get or should I be looking for a newer truck?

    I am wanting to pull a 5th wheel with a boat behind it. Any help is appreciated
    Thanks
    Giorge

    Here are some pics of it

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  2. phoebeisis

    phoebeisis Active Member 1000 Posts 100 Posts

    The dually vs not will cost less than 1 mpg- $2500 over 100,000 miles $4 fuel. $3700 AT $6/gal

    Nice low miles-that is a BIG plus.I love low miles in a used vehicle.
    Looks great well maintained also- huge plus.
    How MUCH?? I'm guessing he wants >$15000 ?? Cost maybe $50,000 for a 2011 ??

    Unfortunately usually sellers want a BIG premium for low miles.
    Our diesel experts will chime in on the specific year problems or goodness.
    In respect to mpg - a dually will be about .7 mpg down hy- more frontal area and more weight- vs not dually.
    A vehicle like that is maybe 45 sq ft frontal area- .5 cd so acts like 22 sq feet-add about 3 sq feet more frontal area for the dually bulge-about .5cd nice clean looking bulge-so 23.5/22= 1.07 or 7% more frontal area -at 60mph this means about 3.5% more fuel use per mile-figure 1/2 mpg.
    At 60 mph roughly 1/2 the fuel is use to overcome rolling resistance and 1/2 fuel to overcome aero drag.
    I would bet your RR is maybe 30% higher with 2 more tires?? So maybe subtract another .2 mpg
    Overall hy down at most .7mpg

    City mpg is all about WEIGHT!! How much heavier is a dually- maybe 400 lbs or so?? 7000 lbs/6600lbs=1.06 or 6% heavier- increased weight is poison for city FE- figure 6% more weight means 4-5% more fuel used. Once again maybe .5 mpg.
    But once again you have more rolling resistance-6 tires- subtract another .2 mpg
    Crude guess you'll lose less than 1 mpg city about the same HY.

    Overall crude guess you'll be down less than 1 mpg vs 4 wheels tires highway and city. Figure 6% down- 10 mpg over 100,000 miles
    10,000 gallons vs 10,600= 600 gallons more over 100,000 miles- $2500 or so in fuel at $4/gallon- $3700 at $6/gal

    If you are looking just at total cost of ownership- consider a gasoline engine-6 liter or even a guzzling 7.4 or 8.1. They will be down about 30%-40% in mpg but diesel cost about 15% more $3.25 vs $3.60 -so it is maybe 25% better in actual cost per distance traveled.
    Spark motored vehicles- used- are much cheaper to buy.

    But DIESELS do pull better- even better than the 454 502.
    For pure $$ and cents the spark motors are cheaper to own/use cheaper to maintain..
    But for pure towing "Goodness" the diesels always win.
    Cheapskates buy gasoline GMs trucks-they are pretty good motors- cheap to fix cheaer to buy.
    Folks who tow constantly prefer diesels because they "tow better" which means they accelerate faster.
    You already know this of course. I see you own a diesel already and many spark motored vehicles.
    You have already DISCOVERED what a fine reliable motor the POWERSTROKE 6.0 is.In general the Duramax-Isuzu design- is much more reliable.
    DIESELS in general are MUCH MORE EXPENSIVE to repair than GM spark motors.Part of this is the GM spark motors and EFI are VERY VERY GOOD RELIABLE MOTORS.
    Diesel fuel systems are finicky expensive SENSITIVE little SOBs. I suspect that many filling stations have water contaminated fuel tanks. A little water is no big deal for gasoline motors- apparently it is a BFD for diesels!!
    DIESELS ARE FUN- GET GREAT MPG- PULL GREAT- but they are EXPENSIVE. Hard to beat a GM small block gasoline motor for inexpensive getting where you need to go with lots of "stuff".

    18 wheelers have sturdier much more expensive and reliable FI systems probably have better water removal filters also.They aren't building their FI systems to be "cheapest possible" they are building them to be MOST RELIABLE- initial cost to build be dammed.Unreliable means lost $$$.Yeah Ford cheaped out on the 6.0 PS- what a BIG surprise. Their latest PS- is said to have no cheap outs?? Ford has gotten smart I think.We'll see.
    Charlie
    PS sorry about the essay- I'm supposed to be preparing a lesson- Biology General Science- for 90 Louisiana public school kids-substitute teaching- tough way to make $62/d.Nice kids, but not particularly motivated or inherently interested in math/science/technology.I'm goofing off.
    Last edited: Feb 27, 2011
    1 person likes this.
  3. giorge

    giorge New Member 100 Posts

    Thanks, I just haven't talked to anybody that has a dually so I wasn't sure on the mileage and I know that there are some years of trucks that had problems and I hate buying a truck that is going to have problems.
    The GMC 3500 is $27,000 and I am also considering 2 other trucks, an 06 GMC crew cab Duramax(black) with 77,000 miles and a $28,000 price tag or a 2005 Chev extended cab (white) for $25K with 44,000 miles and am trying to decide which one is the best way to go for pulling a 5th wheel with a boat behind.

    I have considered a Dodge but I am a GM guy, I won't even look at a Ford, the one I have for work is a total piece of crap, it has 166,00 miles and has had 35 injectors, 6 turbos, 6 EGR valves, high pressure oil pump, fuel pump and injector pump replaced. The company I work for is getting me a new chassis (Ford) with a V10 and doing away with the diesels, my truck weighs 19K. This should be interesting since I have to go over a mountain pass every day.

    some other pics.

    [​IMG]

    [​IMG]
    Last edited: Feb 27, 2011
  4. phoebeisis

    phoebeisis Active Member 1000 Posts 100 Posts

    Lots of companies sour on diesels.
    They are supposed to "last forever"- pure BS- the injections systems are just to dinky-and too expensive.
    They have found it is cheaper to just get a big spark motor and eat the extra fuel cost.
    The V-10 Ford is decent enough- but it is a HORRIBLE FUEL GUZZLER- worse than a 454 or 502.Hey you don't pay for the fuel, so who cares.

    Wow those diesels are expensive suckers. Wait a few months until Diesel hits $4.50 this summer- all big vehicles get cheap when fuel goes up in cost- especially with the diesel premium.
    Yeah wait for fuel to spike a bit more- prices of big vehicles will go down.Lotta folks bought 3/4 ton diesels for fun- not much fun when diesel is $4.50.
    Charlie
  5. DAREDEVIL

    DAREDEVIL New Member 1000 Posts 100 Posts

    for pulling a 5th wheel, 100% go dually !!!! what size boat BTW ??
  6. giorge

    giorge New Member 100 Posts

    The boat is a Sea Ray 185S (19.5 ft) with a V6.
    I haven't considered a dually in the past because I always thought the diesles would get crappy MPG like the gas dually. But since I am going to buy a 5th wheel and pull tandems I have been reconsidering getting a dually.
    2 guys I work with pull tandems and neither use duallies, 1 has a Dodge Cummins the other has a 2500 Duramax and they don't have any problems "yet".
    But I am not them, I have seen some nasty accidents with tandems. That's part of the reason I am considering a dually.
  7. DAREDEVIL

    DAREDEVIL New Member 1000 Posts 100 Posts

    well, for a 20 foot boat you neither need a dually or a fifth wheel trailer..but it is much safer with a dually. Milage on a diesel is always way better then on a gas engine.
  8. giorge

    giorge New Member 100 Posts

    I am looking at a dually for stability, just mainly where I go some of the passes can be nasty at times. The one I go over everyday is 6000ft. the one up to the lake I go to is 7700ft. and has some steep and windy roads. The guys I work with both have 3/4 ton trucks and both pull tandems. I was just thinking of the stability of a dually compared to a standard pickup. Some tell me to get a dually some say a regular truck. Just trying to get all the input I can get.
    Last edited: Mar 4, 2011
  9. phoebeisis

    phoebeisis Active Member 1000 Posts 100 Posts

    No question that a modern Turbo Diesel will be a much better feeling tow vehicle-ESPECIALLY since you have to gain altitude.
    A BB spark motor(454,502) will get horrendous mpg towing a 8000 lbs of anything in mountains and hills-maybe 4-7 mpg!!!!
    A diesel might actually double mpg in that situation.
    The dually in a diesel won't impose much of a mpg towing penalty( much less than 1 mpg while mountain towing)- not enough to worry about-especially towing uphill.
    Modern turbo diesels always "feel better" towing than spark motors- much higher compression+ maybe 15psi of boost+ no throttle plate blocking the intake.
    They can produce maybe 50%-75% more torque at low RPM-maybe even double in the mountains at altitude.They have an inherent 30-35% FE advantage and there just isn't any way around that(except complicated heavy delicate expensive gasoline electric hybrids).
    Turbo diesels are EXPENSIVE- but they tow better- no debate there.
  10. DAREDEVIL

    DAREDEVIL New Member 1000 Posts 100 Posts

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