Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Can changing oil change gas mileage? *UPDATE* Gas mileage sucks again!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jjlaughner, Jan 10, 2003.

  1. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    OK, so here's the deal. In Dec I changed my oil as usual Valvoline MaxLife 10W30... WAIT, I grabbed a box of 10W40!
    Go ahead with the oil change. Well about that time I got bored one day and made up a sheet in excel to track my $ and miles in the K5. I drive on average 600miles a week and go though a fair amount of gas and oil changes. Started the first line as 12.98MPG, which is about what I figured it got. Next fill up was 13.87, 14.02, 14.94, then the snow came and 4wheel driving kicked in 13.34. So on and so on. I just added my last fillup up and its almost 16mpg. Grant it floats with city driving, ideling, warming up when its cold, and playing. But the 16MPG came right after I done my oil change again, switching back to the 10w30?
    Just seems odd that it jumped up right after the oil change. No different driving habits, still let it warm up a few minutes and I'm running 70 into the wind still! /forums/images/graemlins/smirk.gif
    I guess we'll see what the next fillup is! MAYBE 17MPG /forums/images/graemlins/grin.gif
    Gas Tracker

    Constants: I use my debt card to keep track of gallons and dollars and I write the mileage on each receipt after the fillup. Each fillup is at the same pump 90% of the time and I let the pump kick off when its full.
    I guess I should mark the times/dates that I use 4WD? Only twice on the highway I can think of. 12/16 & 12/24
     
  2. Muley

    Muley 1/2 ton status

    Joined:
    Sep 26, 2002
    Posts:
    364
    Likes Received:
    0
    Location:
    Eagle Mountain, UT
    Re: Can changing oil change gas mileage?

    So you noticed the mpg going up with the 10-40 oil?
     
  3. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    Re: Can changing oil change gas mileage?

    no, I noticed the gas mileage go UP with the recent oil change back to 10w-30 Maxlife. I use 10w-30 Maxlife, always! Last month (12/01/02) I grabbed a box of 10W-40 and decided to go ahead and use it since I was already in the middle of the oil change. That week I also started the GasTracker (12/04/02). After my oil change a few days ago (01/06/03) I noticed the MPG jumped up with my last fillup (01/08/03), which was after I switched back to the 10w-30. /forums/images/graemlins/deal.gif

    SO, I dont really know what it was before the 10w-40 because I started the tracker after I used the 10w-40. Now that I have the usual 10w-30 back in it the MPG jumped up /forums/images/graemlins/eek.gif

    I guess its more of an idea than a question, just wondering if anyone else has noticed this?
     
  4. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Re: Can changing oil change gas mileage?

    You should see what changes you will see when you switch to synthetic 5w30.
    I did.
    The thing is the higher the number the thicker the oil, and that means a little more drag.
    Actually if you noticed the milage increases as you go because the oil starts to break down and when you change it it's almost like water right?
    although the multi grade is suposedly the first number is the viscosity and the second is the heat range = 10 is the viscosity, or thickness, and 30 is the heat that this oil is made to handle and NO it's not the actual heat number but the classification.
    Usually in the summer when it's hott and oil will thin out faster they recomaned higher numbers, at winter times the oil will get thick and make it harder for the engine to turn so they recomend lower numbers.
    MOBIL 1 even made an oil 0w30 which is supposed to be still liquid at freezing tempratures and yet be able to handle the heat that a 10w30 can handle.
     
  5. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,075
    Likes Received:
    486
    Location:
    Grand Rapids area
    Re: Can changing oil change gas mileage?

    A couple things to keep in mind about mpg:
    -The pumps are not always accurate. Sometimes they are accurate at certain points, like 5 or 10 gallons, but not necessarily at points inbetween. This is because they are always checked for accuracy at certain gallon amounts. Yes, it's dishonest. Plus, they can drift inbetween calibrations. I once paid for 17 gallons of gas for a car that never held more than 15.
    -How full it is at a fill up can vary a bit from fill up to fill up. It's best to let things average out over time and it's difficult to get an accurate mpg figure from any one tank.
     
  6. Tuff84blaze

    Tuff84blaze 1/2 ton status

    Joined:
    May 12, 2000
    Posts:
    119
    Likes Received:
    0
    Location:
    Liberty Lake, Washington
    Re: Can changing oil change gas mileage?

    Man Id be a Millionaire if I could get 16mpg.

    OK maybe only a thousandaire /forums/images/graemlins/grin.gif
     
  7. unsane

    unsane Guest

    Re: Can changing oil change gas mileage?

    Ive got as hard back notebook I keep in the truck to write down the gallons, price, and milage each time I fill up. I also write in oil changes and other maint. in this book. I used to think this was ANAL when a friend of mine did it, but now that I have tried it, its really pretty good idea.
     
  8. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    Re: Can changing oil change gas mileage?

    Yeah, I just thought it was odd being right after the oil change? Thats why I started an excel sheet to track this stuff, It has the average total at the bottom.
    As far as fillups I usually go by sound, I can tell when its getting full by the sound/gurgle it makes. Usually the pump kicks off just then or it makes a whisteling sound then start to bubble out. I got good at judging it so I dont have to clean the over flow gas off the paint. Thats why I like to use the same pump at the gas station about half way between work and home (usually no one is at it around 11PM on my way to work since its a credit card only after 8pm!).
     
  9. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    Re: Can changing oil change gas mileage?

    Yeah, I use to switch back and forth in my 'Other Make' Pickup with a 318 3 speed on the column. 40 in the summer and 30 in the winter and it ran great. I never really seen to much of a difference in the /forums/images/graemlins/k5.gif other than it turn darker quicker but running on the highway all the time I change my oil at least once a month some months twice (beginning and end of the month)!
     
  10. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    Re: Can changing oil change gas mileage?

    I like it, it helps me keep track of my spending on the /forums/images/graemlins/k5.gif too. Now I just need to save up for new tires! Gas and oil changes are easy to get to, its that pesky $700 tire thing I have to work at. /forums/images/graemlins/eek.gif
     
  11. JakeInAZ

    JakeInAZ Registered Member

    Joined:
    Jan 11, 2003
    Posts:
    21
    Likes Received:
    0
    Location:
    Near Prescott AZ
    Re: Can changing oil change gas mileage?

    I'm not sure if this will apply to you since I'm not sure what the weather is like where you are but I have recently found luck with in mpg when I switched oil weights. I am in northern Arizona and it goes from 100+ in the summer to snow right now in January. An old man suggested I try Mobil 1 Super Synthetic 15W40 or 15W50. I had the best luck with the 15W40 though. I noticed an increase from 10mpg (sometimes less) to up to 16 or 17mpg on the highway. Granted my engine is far from stock and I have a 750cfm carb, but the 15W40 does excellent in both hot and cold extremes and I burn FAR less oil and have to change plugs far les often. Just an idea....if it applies, great....if not, best of luck with whatever does.
     
  12. jjlaughner

    jjlaughner 3/4 ton status

    Joined:
    Jan 12, 2001
    Posts:
    7,406
    Likes Received:
    0
    Location:
    Indiana
    I'm back to 13.50 MPG again! /forums/images/graemlins/crazy.gif
    Oh well I guess it was nice daydreaming for a couple days about 16MPG! /forums/images/graemlins/smirk.gif
     

Share This Page