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2010 Outback 2.5i
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Discussion Starter #1
2010 2.5 premium CVT here, we usually get 30-32 mpg when the air temperature is above 40 F. Lately here in southeast Idaho it has been blow zero at night and teens during the day, my mileage is around 22-23 mpg! Anyone have suggestions on possible lube changes in differentials? I have Subaru change the oil and they use Subaru 5-30W, and I never go above 70 mph and don't have a lead foot either, thanks!
 

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2010 Outback 2.5i
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23 Posts
Discussion Starter #3
Well my other vehicles, 2001 Dodge Cummins stays steady, in fact the same mileage the Outback is currently getting, year round, my other current gasoline burning vehicles present and past have never dropped nearly this much in the winter time.
 

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2013 2.5i Premium 6mt, Twilight Blue
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5-30W is what you have and what you want. You just have to come to terms that gas mileage is going to be worse in the winter time - longer cold start, ethanol blended fuel, etc. One thing I would check is your tire pressure, which naturally decreases as the air gets colder - make sure the tires are filled to spec and that will at least help.
 

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2010 Outback 2.5i
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Discussion Starter #5
Tires are at spec and filled with nitrogen and pressure never fluctuates, which is nice because when winter hit and regular air was in the tires the TPM would go nuts. Also I use ethanol free fuel from Sinclair, I might add that Sinclair and Exxon fuels have always gotten me the best mileage in this car. Just found it odd the mileage difference I have experienced with this car and never have to this severity with any other vehicle I have owned. I'm checking mileage with calculator not using vehicles system by the way. Anyone feel that a synthetic gear oil would help much vs the installed conventional factory filled oil?
 

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2013 OB 3.6R SAP
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203 Posts
How many miles on the car? It's possible you have some other issue with the car that is unrelated to the weather, like bad plugs or O2 sensor. Has the car always had bad mileage in the winter?
 

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2010 Outback 2.5i
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23 Posts
Discussion Starter #7
New plug and sensor at 75,000 mi car now has 95,000 mi. Been a trouble free car as well and owned since new, CVT has been better than thought as far as reliability but not sure if ill keep it much longer to see how far it will go lol, might be time for the STi I have been eyeing
 

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2013 Outback Limited 2.5i
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114 Posts
Synthetic oil would definitely help, especially in extremely cold temperatures. You might get an additional 0.5-1 mpg. It won't make much of a difference during the summer, and when your engine reaches operating temperature. Your best be would be 0w30 synthetic, which is a direct replacement for the 5W30 recommended by Subaru. Walmart sells Mobil 1 0W30 AFE for about $25 for a 5 quart bottle. Other brands are available but are usually more expensive.
If you make a lot of short trips you will see more of a benefit.

Wear on your engine will also be less.


Finally, replacing the stock tires (if you haven't already) with a lower rolling resistance tire would also help. That would probably make more of a difference. You might want to increase the pressure by 2lbs or so too.
 

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2010 Outback 2.5i
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Discussion Starter #9
Running Michelin's best tire that is supposed to be more efficient. I had those POS Continental tires gone within a month of buying the car, which also solved the front end vibration issue that so many people seem to be complaining about with the new outbacks, tires are usually the first to go on my new vehicles, every manufacturer seems to put the cheapest tire they can on their cars, never has changed lol
 

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2019 2.5i Outback Limited, CVT, Nav, Eyesight and the rest of the safety stuff.
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I have a '10 Limited CTV and live lived with a winter mileage drop every winter since I've had it. I'm sure its the longer warmup time, since it seems to even out some on long trips. But on my daily commute (about 8 miles one way), I go from 26-27 MPG to about 22 MPG during the winter. (Our local gas also goes to winter mix, which cuts into MPG.)
 

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It must be a hugh difference with 99% highway. 63 miles each way to work. My wife drives within 10 of the limit and always get 29-33 average. She has never gotten less than 29 on a tank doing it long hand. We went from Kent Island Md to Ocean City this summer running a straight run @ 55-60 mph non stop and got 34. Winter gas is still at 29.4-30.9.
Again a very light foot and Amsoil Synthetic oil. Tires are set at plus 3 on the door jamb. 40,000 on a 2012 and the tires still look new and are smooth as glass. Zero oil burn.
I hope our 2014 will be as good when it comes in this spring. We only keep our cars 18-24 months. My wife wants to keep this till it dies, and the way this one is running could be a long time off.
 

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2013 OB
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It must be a hugh difference with 99% highway. 63 miles each way to work. My wife drives within 10 of the limit and always get 29-33 average. She has never gotten less than 29 on a tank doing it long hand. We went from Kent Island Md to Ocean City this summer running a straight run @ 55-60 mph non stop and got 34. Winter gas is still at 29.4-30.9.
I'm getting what you are both in summer and winter. I notice about a 10% drop with all of our other cars in the winter, so makes sense I'm getting ~29 currently with the 10% ethanol. (70mph freeway). All stock, Subaru synthetic oil.

I really can't ask a 3,400lb bloated AWD family hauler to do much better.
 

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'18 Outback, an F350 for big stuff
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Cold weather driving seems to take a toll on fuel mileage. My experience is a 6 MPG loss from summer to winter driving. This is with synthetic oil and all the other things that one can do to improve mileage.

I really think that these (and other) engines are less efficient in cold weather. This shows up as a drop in MPG. Anything that we can do to keep engine operating temperatures in the normal range would help. Unfortunately, new vehicles do not come with temperature gages so actual engine operating temperatures are not ovbious.

Time to hook up the laptop to the vehicle and see just what this OB runs at in the cold weather.

The MPG is still *much* better than my F350, so I am really not complaining.

Lou Braun
 

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2011 Outback Premium CVT, AWP, Steel Silver
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Sounds about the same for me. I am getting 22 right now with winter blend fuel and cold weather.
 

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2017 Outback, 14 Jeep Grand Cherokee, 07 BMW E-93
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You get down to zero outside and you have a significant amount of resistance that has to be overcome. It doesn't matter if you have ethanol or not because the gas is reformulated which accounts for (according the EPA) around 7-8% loss. Difference between your 2.5L and the diesel which has so much torque is also huge. When it gets cold my diesel mileage drops but nothing like what you report. It makes sense you have AWD driving all wheels to some extent. I plan to change the diffs anyway to synthetic to reduce friction but also extend life.
That might help as suggested but I think you are dealing with a fact of physics. Zero is some of the harshest conditions out there for our OBs...
 

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2011 Outback
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I'm getting killed right now with winter mileage. I'm under 25mpg and it takes a long time for my blue water temp light to go off. It's only for about 90 days so I'll just patiently wait until March.
 
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