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Break in time and gas mileage

17K views 21 replies 18 participants last post by  JTWayt 
#1 · (Edited)
Hello all,

New member here. Just picked up our Touring 2.5 on Oct 8th. Must say we love it but I have a few questions.

First off our gas mileage is what I consider way sub par. Now we only have about 680 miles on the engine so far. We have been averaging on first tank about 17.8 mpg and second tank 19.2 mpg. So far third tank is in that 19 mpg range. When I asked the service manager at the dealer they told me that this is normal for the break in period. She even told me it could take up to 12k miles to fully break the engine in. That really seams like a load of manure.

We have been taking it really easy on the engine. There has probably only been twice that we have gone above 3500 rpm and that was only for a few seconds to get out of situations on the freeway. For the most part the car will be about 80 % city and 20 Hwy. I know sticker says 26 mpg city. I am not happy with the close to 25% less than advertised mpg of 26 city. Even when we are on the hwy the on board will give us a readout of about 25 mpg average.

I guess what I am getting at is, just how long is the normal break in period?
Will my mileage go up ?
I was considering taking the car in at 1000 miles to get the oil changed even though service manager says it does not need to be done until 6000 miles.
If my mileage is still way sub par at 1000 should I take it in and create a ticket in Subaru system about my lack of mpg ? This way I can start creating a history report.

I am sorry for sounding a bit paranoid. This is my wife and I first new car purchase. We have never owned a new car before and I want to make sure I am doing everything right to make sure it last for a long time.

Thank you all for any help you can provide me.

Add on, We have been keeping a log book recording the odometer and gallons filled up then doing the math.

Larry
 
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#2 · (Edited)
12k mile break in is total crap, try 1-2,000 miles. 1,000 mile oil change is a good idea, even if everything is going great. Are the mileage numbers you're quoting off of the display or actually calculated? I suggest actually doing the math and average several fill-ups.

Having lived in CA before, I can say that you may get slightly less then advertised just due to traffic and the stupid gas they have there. 19 is pushing it tho.

Good idea to get it marked down on the record just in case it doesn't improve.
 
#3 ·
Welcome to the forums! This is my first Subaru and my last car was a lightweight Honda Fit that consistently got good gas mileage. So it took me some time to get used to how to drive the Forester efficiently.

Since I've had the 2.5 Forester my gas milage has varied greatly depending on the driving environment. I found that I get excellent gas milage on the winding back country roads where you can gain lots of momentum. 35 MPG wouldn't be very unusual for me in that situation. With some mild hypermiling techniques I've gotten it up to 42 MPG. However when I'm driving down the interstate going 75-80 MPH my fuel economy drops to 24-28 MPG and can usually get 27/28 consistently setting the cruise control at 70 MPH. In stop and go traffic in the city I expect to get about 19-22 MPG. My lifetime fuel economy is right at 28 MPG over 7000 miles (mostly highway with the cruise set at 70).

19 MPG is a little concerning. I would also say it's a good thing to bring up to the dealer and have it documented. It's better to be safe in this situation than wait and hope it gets better. My gas milage didn't seem to change at all through the break in period.
 
#4 ·
Having lived in ca, you will never get the posted mpg. The sludge they call gas is pathetic. Too many detergents to make the engine run "cleaner", but worse and poor mpg. The numbers are based on no electronics on, flat road, and constant speed and accelerator input. The city is slower and has stops, and theoretical traffic.

80% city, 20-23mpg I would consider normal with such a new engine. 22-25mpg somewhere from 5k-12k should be normal.

Subaru engines tend to setteling down somewhere between 5-10k. So the service Mgr saying 12k is not out of norm, just more on the safe side.

And remember, your driving style has more affect on mpg than just about anything. Light foot and steady wheel = more mpg. Heavy foot and loose wheel = less mpg.

Ben
--------------------
'14 outback 2.5i sap w/ eyesight
'14 tribeca
'17 FXT Touring eyesight on order
posted from Samsung gs7 active
 
#5 ·
Break in ?

The only things iv'e seen about break in was not to use the cruise control or rev over 4k, and the dealer still said you don't need to change the oil until 6 months or 6k miles..... Old school you always changed the oil before the normal recommended time or miles.... Never heard of break in effecting gas mileage... I've found out so far if you run 55 to 65 mph on highway you will get those 30 + MPG, 70 TO 80 mph your back into the 26 to 29 MPG. If your in the city and a drag racer from light to light don't even worry about MPG it's going to be low like 20 to 25 MPG, if you're a conservative driver in the city stop and go traffic you can increase your MPG to 25 to 28 in the city...
 
#6 ·
Old school would come from the factory with a special oil formula to help seat the rings and other bits. This was mainly because the tolerances in manufacturing were so big. Now days the tolerances are so tight that they no longer need to use the special formulated oil and is ok to go full 6-7k before the first oil change.

Ben
--------------------
'14 outback 2.5i sap w/ eyesight
'14 tribeca
'17 FXT Touring eyesight on order
posted from Samsung gs7 active
 
#7 ·
...is ok to go full 6-7k before the first oil change.
...
Sounds good to me. I suspect that in the "good old days" engine assembly was dirtier than today - more chips and stuff left over. That, plus un-seated rings that allowed more blowby. All of this risked filling up the filter and polluting the oil, thus the earlier change requirement.

I went the full 7.5K miles on my new car and took apart the filter to see what it had picked up. Not much. Just a few tiny red specs - probably sealing compound.
 
#8 ·
I recommend doing the first oil change because it removes the abrasives from the initial break in that the oil filter misses. Oil filters do not remove all abrasive particles. After you have about 3,000 miles on your Forester you should be getting about your best fuel economy. Depending on the quality of fuel, traffic, climate, trip length, and driving style will determine your fuel economy and not the EPA. EPA = Enormous Propaganda Agency. By the way, my actual city fuel economy is 15.1 mpg tested in New York City which is a real city, not some town or a dyno. that the EPA uses. Hy-way has been 28.5 to 34.1mpg so far.
 
#10 · (Edited)
For my past three cars, on which I record each tank, my mileage is highest during break in. And then drops after break in. Because during break in I take long drives on twisty hilly back roads to vary the speed and throttle. And after that I drive normally around town, with short errands, hopping on and off the Interstates, being part of aggressive traffic.
 
#11 ·
Sorry for the update delay everyone. Just filled up our next tank. Still getting around 19.5 mpg. Mostly city driving with a couple of 10 minute freeway jaunts. We are around 800 miles on the engine right now. My plan is still to take it in at around 1000 to get the oil changed and log a issue with Subaru maintenance records about my lack of gas mileage.

Thank you all for your responses, I will keep you all updated as things go along.

Larry
 
#14 ·
19 mpg sounds pretty typical for city driving. It's what I get around town. Low speed, and lots of idling. I'm getting 26-32 mpg driving a 54 mile round trip on rural roads. I get 32 mpg going (downhill with 700 foot elevation loss) and 26 mpg coming back. This has been consistent from day one and 10 miles on the odometer. Freeway driving I'm getting around 28-30. Changes with the seasons when they change the ethanol content of the gasoline. Winter fuel has less latent heat than summer fuels, so less mileage.
 
#13 ·
I've owned 16 new cars and the Mileage improved on all of them after a few thousand miles except My 2012 Mazda 5 which didn't peak until almost 12,000 miles. Keep in mind it's not just the engine that breaks in, it's every moving part. Trans, bearings, differentials, all have a break in of some sort and a car with 4 wd or AWD has even more moving parts. I got better mileage than you did on crappy 10% Ethanol Crap Midwest gas, perhaps that Commie California Gas is even worse?
 
#15 ·
Hi, Just new to the forum but just bought a 2017 Forrester 2.5i. Only 2100 KM on it now and in the Canadian form, l/100km Mostly highway speeds in winter with studded snows, average 8.2-8.4 l/100km. I think that converts to about 34-35 mpg. See how it goes later after break-in and summer tires.
 
#16 · (Edited)
Hi rossmx,
The conversion from l/100 km to mpg in you car is not 34-35.
It is 28-28.5
Just to let you know. I got mine a couple of weeks ago with m/t and it is giving me 29 mpg. I have only 780 miles.
Keep us updated with the gas consumption, because I always said, it is an indication of a problem if suddenly the vehicle start using more gas than normal.
Thanks for the info.


Sent from my iPhone using Tapatalk
 
#17 ·
Hi! New member here

I have just over 800 miles now on my 2017 Forester Touring. I absolutely love it but was wondering if other owners are also noticing that they get better gas mileage on city roads vs. highway? I'm certainly not complaining about my mpg but find it odd that I'll get 30-34 mpg fairly easily while driving on "city" roads in stop and go traffic but struggle to hit 27+ on the highway.

I've made a few trips in the New England area now and noticed I still get better gas mileage off the highway. I've noticed that it I keep the speed around 65mph I get 25-27mpg whereas if I go 70-75mph I'm hitting 28-30mpg. This is my first Subaru and first AWD vehicle so I'm just trying to get an idea of what's normal.
 
#18 ·
I just passed the 1,000 mile mark on my 2017 2.51 and I've got a lifetime MPG of 26.5. Most of that has been freeway miles, where I am seeing 30s and even 40s pretty consistently. It's even hit 50 MPG for a couple of short stretches, while I had cruise control set to 74 and was heading down a steep stretch.
 
#22 ·
Some of it depends on driving before the engine warms up, and it takes longer in a cold winter. Short hops don't yield good mileage, best to avoid during break-in. Recently I took a 40 mile freeway trip having about 720 miles on the car, and the computer gave me 39 mpg going there. The return leg went thru more city, and had worse traffic on the freeway, so it booked 29 mpg.

I do citizen's watch in my neighborhood on a 13 mile course, rarely above 20 mph, usually 15 mpg. I try to keep my acceleration below 15%. The computer gives me 23 mpg.
 
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