Durango improves gas mileage----why ? how?



I have a 2003 Durango, its already poor mileage slid in the last year to 13 max. Recently I had my mechanics, G and E, put in long distance motor oil by Valvoline as it was starting to use a quart every 3 grand or so. I also just had the tires rotated, but, they were fully inflated before the rotation. Question is "Did the oil, the rotation, or neither of the above, contribute to a shocking hike in mileage to 15 to almost…17 in the last five or so fillups ??

Signed, Too good to believe.


Check the compression. It is possible that you have had enough engine wear that the oil has helped increase the cylinder pressure, but it is not likely it will bring it back to normal.


If these were the only changes during this time, then yes, we have to attribute the mileage improvement solely to the new type of oil and to the tire rotation. There’s nothing else.

But… We are in the same situation as when a poster reports a sudden drop in mpg. He has left out something. There’s something else he is not telling us. Most likely it is a significant change in driving habits. It could also be a math error in determining mpg, or a misinterpretation based on his methods of calculation. Naturally he denies any chance of his own mistake.

So there you go, macmeridiot. Accept the explanation of oil and tires, and think no more about it. It least your mpg has gone up not down.


Maybe they inflated the tires to the right pressure when they did the rotation. That would be the most plausible explanation IMHO.


To get the best mileage you can, Tom & Ray have drawn up a list of some helpful ideas. Go to the bottom of the post page, click on Actual Car Information, scroll down the page to Guide To Better Fuel Economy. You might get that mpg up another notch!


Did you have the thermostat replaced after the mileage went down but before it came back up? If the engine was not running fully warmed up, as would be the case if the thermostat was stuck open, I can see where the mileage would drop. Your mechanic might have replaced the thermostat if you complained that the heater wasn’t putting out warm air. After seeing all the other postings about “possessed” cars and cars with a mind of their own, did the Durango perceive that it might be traded and wind up on the auction block and decide to clean up its act?