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#323 of 19283 Fuel efficiency problem??
Oct 09, 2002 (11:45 am)
It's time for a 60K service and I need some advice. I have a 1998 Sub Legacy that I bought in October of 2001 with about 30K miles on it. Now I have 60K miles and I've experienced a huge range in fuel efficiency. It seems to be related to ambient temperature. In outdoor temperatures above 70 degrees F my gas mileage will be over 300 miles on an 11-gallon fillup (I am a slave to routine). Once it's below 70 degrees, the mileage drops to about 250 miles per fillup, even on long drives (VT to NJ) at highway speed.
I buy Mobil or Shell gas because that's what's available. This is not a hard-starting car, it seems to warm up "normally", it seems not to make unusual noises, doesn't have clouds of blue or white smoke from the exhaust. I have a 20-minute stop-and-go daily commute, but I have a 65-mile highway drive (one way) to the country every weekend. And there are those occasional trips to NJ.
Is this kind of mileage difference unusual? My dealer's service department is not filled with energetic, enthusiastic problem-solvers. I need to spell things out for them in grim detail.
My son the Volvo mechanic said if this were a Volvo they'd check a temperature sensor. What should I tell the Subaru mechanics?
Thanks for the help.
Elizabeth near Burlington, VT
#324 of 19283 Temperature does affect mileage.
Oct 09, 2002 (12:28 pm)
But the only time I've seriously noticed it is late-fall to winter. Combustion is lower when heat is lower. Remember last summer when firefighters would pray for colder weather to keep flames down? Same thing happens with a vehicle.
Oct 09, 2002 (12:28 pm)
Trivia tidbit for you: VT is the state in which Subaru has its highest market share.
What oil are you using? My guess is they put in 10w40. I would use a thinner oil, 10w30 or even 5w20, when it's really cold out.
Another thing to consider is an engine block heater. You'd leave it plugged in so that it's already warm when you start it.
At really cold temps, you'll get approximatley zero miles per gallon until the engine warms up.
Oct 09, 2002 (1:16 pm)
In some states the gas itself is different in winter than in summer. More corn-brewed alcohol in the mix. So summer and winter gas mileage could be different because the gas itself is not the same. Or so someone told me.
Oct 09, 2002 (1:24 pm)
I'll second what Steve said regarding "winter blend" (oxygenated) gas. The blends used here in the Midwest decrease my mpg in winter by 2-3 mpg.
#328 of 19283 Oxygenated Reduces mine by a lot.
Oct 09, 2002 (1:58 pm)
I try to drive out of area to at least get a blend in during the winter because it drops so low. Average regular fuel mileage 26-28. Average oxygenated 19-22.
Oct 09, 2002 (2:10 pm)
Now that I think about it, my mileage drops by about 2mpg in the winter as well.
Still, try the suggestions above, maybe change brands of gas and track your mileage to see what helps.
Then share the results with us, of course!
#330 of 19283 fuel efficiency advice
Oct 10, 2002 (7:17 am)
Thanks, all. Yes, VT has zillions of Subarus on the road. Not around Burlington, though - more in the central and Eastern part of the state where dirt roads and steep hills make AWD a blessing if not a necessity. Volvos, Saabs and Toyotas plus the domestic makers still abound in Burlington. There's one Subaru dealer here and no independent mechanics (that I've found) that work on Subes. Sigh.
We also have oxygenated gas in the winter. I know I get lower gas mileage at temps below 40 (winter range temps). My question came from wondering why gas mileage changes at the 70-degree F outside temperature point, because I'm getting "winter" gas mileage most of spring and fall. Well, I shall try a little of everything and see if I get a different result. If I have any news to report (in the spring, I guess) I'll let you know.
#332 of 19283 Where is the water going?
Oct 13, 2002 (6:23 am)
Hello, we bought a six cylinder Outback a few months ago and my husband has to add water to the car every time our daughter returns home from school. The dealer has checked it out, tested the cap? and says nothing is wrong. As winter is coming we are getting nervous, don't want her to get stranded on the side of the road somewhere, suggestions or information would be greatly apprecaited.