Why is my 228,000 miles mpg BETTER now?

Discussion in '4x4's, SUV's and P/U Trucks' started by phoebeisis, Jan 29, 2015.

  1. phoebeisis

    phoebeisis Well-Known Member

    Let me set the stage
    My 1998 Suburban 2 wd-bought for $2950 195,000 miles in 2007
    is our second car
    We needed something when "cash flow" ha,ha problems happened in 2006
    so Pilot Titan Prism got sold ($39,000) and Prius+ancient suburban($22,850+2950)
    got bought-improving family mpg to well above 30-from maybe 19mpg-ongoing fuel savings
    and we retained the ability to evacuate 2 leggy greyhounds 4 or 5 crated cats+3 adults.

    Anyway I sub teach sometimes/
    One school is exactly 10.2 or 10.3 miles away(return leg a bit farther)
    I have made the trip there-last year-many times
    Last year-in these temps-40 DEGREES am 68 degrees pm
    I would STRUGGLE to get to 15mpg on the cold engine trip out .7 gal out
    On the trip home I would OCCASIONALLY hit 16 -but usually high 15's
    Now I am crossing the Mississippi- probably 250 foot altitude gain loss-
    Guessing since I DWL (follow the slowest truck I can find-usually dropping to 40 mph on 50 mph bridge) the bridge is nearly a wash-but doesn't matter since

    My QUESTION-
    Why am I getting 16.2 16.4 16.1 on my 6 trips-in this weather??
    roughly .8 better 6-7% better than usual/.

    Now I did just change the oil-but to my usual Mobil 1 10w30
    I have never thought that Old oil was more viscous(granted it does feel a bit sticky at times)
    I change oil once a year-extended service mobil 1-$31 at WAL mart

    Is there ANY CHANCE that the ethanol content in gasoline has been decreased
    since oil is now cheaper -much cheaper-that ethanol
    Surely the EPA doesn't require a full 10 or 15% ethanol
    Yeah my mpg-seems like "pure gas" MPG
    Not 10% mpg
    What is the GOV actual requirement for ethanol??
    Isn't it quite a bit lower-for oxygenation=than 10%-even in cold weather?

    Now I guess it is faintly [possible I am doing something different
    maybe I am gliding more on the bridge-actually putting it into N
    I never switch off the engine-not even for lights(unless it is a 2 minute light-none on this route-and I glide in D because at less than 40 mph the suburban glideS in D as if it was in N-much above 40 mph and you can feel that trans causing engine braking-
    under 40 mph and when you lift off it is as if the trans has been disconnected from the driveshaft

    So any chance the ethanol percent is down??


    Oh at the time-2007-I would have preferred a minivan-honda toyota-
    but they were 2x the GM
    And in hindsight-the GM has been great-extremely reliable and relatively easy to DIY parts switch-brake booster radiator intake manifold gaskets timing chain and gears(didn't need it)-starter door handles belt tensioner sway bar mount
    and many other things that have slipped my mind
    If I had to have a shop to the repairs-it would have been maybe $7000 or so
    but DIY maybe $1500
    and parts for older GM trucks are cheap and available readily EVERYWHERE

    And it gives 21 mpg on long trips-not horrible considering it is a 5200 lb brick with a somewhat ancient drivetrain( well developed and reliable obviously)

    Secondary question-any 2004-2006 GM 5.3 owners out there??
    Do you actually get the 2 mpg city more than the last 5.7's??
    Mine is rated 12/17 the 2004 are rated 14/18
    they -2004 have much better brakes and much better 14% EPA CITY rating
    Tempted to get one-once oil spikes and the HUGE SUVs become pink elephants again
    yeah owners will bail about big time at $4/gal-last time that essentially gave them away at about $3.50/gal
    and they stupidly switched to mid sized SUVS-to get the same 15%-20% better mpg they could have gotten with mild hyper milling-for $35,000 less

    USA-E-INS really won't do basic arithmetic-they panic-sell sell when they should modify driving habits-and drive less-or drive the actual car-more

    So
    1) Any chance ethanol concentration is lower now that oil is so cheap
    2)How does the 2004 2006 5.3 perform -2 mpg city better than last 5.7s?
    The newer 5.3 with AFM not on the table-rear doesn't "fold flat" too expensive and AFM MIGHT be responsible for increased oil consumption in some models(engines occasionally actually failing-but usually just sucking in 1 qt per 1000 miles or some such-can't imagine that much on in CC does FE plug fouling-any good)
    Charlie
     
  2. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I doubt the ethanol percentage was decreased , though I would sure like that. The ethanol lobby is pretty strong and in bed with all the right people.
     
  3. phoebeisis

    phoebeisis Well-Known Member

    Odd that my mpg is measurably better

    I have always doubted the "new oil is slicker" folks
    still doubt it-
    0.5mpg in the 16 mpg range is quite a bit 3% or so

    There is PURE GAS GAS- and gas is now cheaper that ethanol-so….
    I have noticed the Pure station wants $2.19 for 87%-shell 87 is just $1.87
    used to have just a 8 cent spread
     
  4. geezzz I wish. cheapest I've found pure gas around here is still mid $3.xx
     
  5. 08EscapeHybrid

    08EscapeHybrid Moderator

    It is possible since gas is cheap, that the ethanol content may have slightly decreased. A brand new oil change helps too. You also have more experience driving the vehicle. I have a question though, why are you using 10W30? The manual calls for 5W30, and as long as you don't have an oil consumption problem, 0W30 runs great in them.

    I run 5W30 in my 81 Buick (calls for 10W30), and I run 0W30 in my 98 K1500. It runs like a champ on the 0W30, and I'm not having any oil consumption problems (about 192,000 miles)
     
  6. phoebeisis

    phoebeisis Well-Known Member

    The step child-James-it went up a bit yesterday $1.89 for shell 87
    Yeah terrible- $1.89 gas
    frankly I never saw that coming
    But I certainly see a price spike
    soon enough

    So "new oil" is worth something" always wondered about that-
    older oil-always "feels" stickier-and I always seem to get some of the damn oil on my hands-even gloved-old oil "feels" stickier

    08 ESCAPE-
    Why 10w30-?
    Right it calls for 5w30
    Three reasons-overly cautious probably
    1) My oil pressure-full summer would drop to "under 20 psi" maybe 17 psi-yeah I know that is OK- but it is "old" in service since 1997-228,000 miles
    2)I have an oil leak-probably the front of the oil pan -where it meets the plastic timing cover-but maybe not-and I had an IDIOT change my intake manifold gaskets-he talked a good game-but attacked it with an electric wrench-when I went back to correct his many screw ups-cracked the new plastic timing cover
    I found he had PARTIALLY stripped many screws-
    a)the big bolt that holds the harmonic balancer on(replaced it but couldn't bring myself to crank it all the way up to 70 lb ft(left it at 55 ft lbs)
    b)he oil drain bolt
    c) some oil drain screws
    d)who knows what else
    So I am not really up for chasing down an oil leak-finding all those stripped screws-which are holding-4 years ago-just to save one quart per 6 months(only drive 3000 miles a year)

    So heavier oil-leaks a little more slowly
    3)And I switched to 10w30- couldn't measure ANY DIFFERENCE- yeah there MUST be a penalty to pay-but it must be less that .2mpg-city and maybe ZERO long hy trips(made one with new oil- almost no difference 21.2 21.3 over 3020 miles-pure hy)

    Yeah it doesn't use oil-just leaks it
    Couldn't possibly get such good pure city mpg if oil was getting into Combustion chamber

    Maybe it is "just my driving" changed in some way I am unaware of..... but I am pretty compulsive,so....


    Thanks all
     
    Last edited: Feb 1, 2015
  7. 08EscapeHybrid

    08EscapeHybrid Moderator

    I guess if you're having leakage issues... I haven't bought any 10W oil in years. I've been using 0W30 in my K1500 for years, except for a short period where I had a leakage issue, and I used 0W40 until I had it fixed. My mechanic did a great job replacing the intake manifold gasket when it failed, and haven't had an issue since.
     
  8. phoebeisis

    phoebeisis Well-Known Member

    Yeah
    Definitely leaking oil
    and some coolant is leaking-from somewhere "near" the water pump
    but like I said-reluctant to pull anything off since I know beyond a shadow of a doubt
    I have "many" stripped screws
    I used Bars stop leak-pellet stuff-
    worked great-huge surprise
    went for 1 pint per 20 miles-to one qt per 6 months(maybe 1500 miles)

    Obviously I wish I had never let that "mechanic" anywhere near it
    Still I only leak a quart of oil and coolant per 6 months-so no big deal
    I can get a NEW GM GOODWRENCH for $2100 delivered curbside
    so it will run "forever"
     
  9. 08EscapeHybrid

    08EscapeHybrid Moderator

    I've never used the pellet stop leak. I know the powdered aluminum stop leak works extremely well.
     
  10. priusCpilot

    priusCpilot George

    The best stop leaks are from blue devil.
     
  11. phoebeisis

    phoebeisis Well-Known Member

    Prius-good to know-blue devil huh
    I used the Barrs stuff
    yeah Big pellets-big as BB's
    apparently they dissolve-or Melt-
    and "gum up" the hole-seal it
    I hadn't used that stuff-was somewhat opposed to putting something in my motor-that "plugged things"
    but since I figured the motor had a limited life-225,000 miles when I put it in-
    no big deal
    and a new GM GOODWRENCH 5.7 is just $2100(no kidding) delivered curbside with a lift gate truck to dump it on the ground(of course I have to get it into my house-600 lbs-so I'll actually have it dumped on a cart-
    Anyway-what a bargain-$2100-new OEM motor


    Oh-the Barrs leak stop-heavy petrol odor-kinda foul looking too-oily black looking in the overflow reservoir

    Thanks all
    Charlie
     
  12. RedylC94

    RedylC94 Well-Known Member

    Any chance that goo might also "gum up" a radiator or heater core?

    Maybe your engine was just getting nicely broken in at 225K. My Mazda seemed to get better MPG after it passed 500K or so.
     
  13. phoebeisis

    phoebeisis Well-Known Member

    Redy
    Yes is my guess.
    It is the WHY of why I was reluctant to use it
    But because I sorta viewed the engine(after the idiot mechanic)
    as being on borrowed time
    I decided to take the chance on the "plugging stuff"
    Now it MUST just be capable of spanning small to tiny holes or seams
    something like .01" (1/4 a mm)
    Doubt it could plug a 2mm HOLE in a radiator
    but who knows

    Yeah that is ALWAYS the concern with a leak plugger
    Guessing the ones with actual aluminum particles-are more likely to actually plug up a core-especially a core with some age-grit grunge-already deposited

    But I am very happy with how it worked
    and very very happy with GMs 1/2 ton SUVs of this vintage
    The drivetrains-APPEAR to be OWNER PROOF
    and they are relatively EASY TO DIY(lotta room etc)
    really CHEAP TO DIY
    and PARTS are available EVERYWHERE- for low prices
    and the engines-$2100 for a new engine-
    and just $4900 for a 383E drop in stroker IF I ever allow my "BAD CHARLIE" impulses out
    But I bet I would get the same MPG with that 383E- especially if I changed the rear end from 3.42 to closer to 3 (think a 3.07 is available)
    Yeah at my age-almost 64-the 383E shouldn't even cross my mind-especially with my cheapskate and efficiency compulsions
    but.....
    I won't-because soon enough I will be able to buy a 2006-with the more efficient motor drivetrain-with almost as much power as the 383E- for maybe $6000-with 100,000 miles
    so why bother with the 383E-
    The answer is-DON'T!!
    But it still crosses BAD CHARLIE's -reformed hot rodder- mind
    Charlie
     

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