2010 Lower gas mileage after oil change

[alfon]

Be cautious. Dealers may also put in 5 full quarts instead of the recommended amount which is 4.4 quarts (US),with filter change.

When I changed my oil I used only 4 quarts and that was over 7,000 miles ago and the oil level is still in between the marks, about half way. Last fill up was 57.49 MPG, calculated. Oil, 0X20 Moibl 1 synthetic.

alfon

[macdonald]

I just called my dealer's service department and asked about the oil they use in a new 2010 Prius and was told it was 0W-20 synthetic oil.

[DaveinOlyWA]

Red... considering your location AND the time of year, part of your reduced mileage is caused by the switchover to winter formula gas. it will lower your mileage simply because it has less energy per volume. iow, your "gallon" of gas does not have a full gallon in it.

additives were added to lower the freezing point of gas to keep it from freezing in the lines. the additives do burn, but do not provide as much energy. you will lose 2-4 mpg if nothing else changes.

now, i know what your weather has been like the past week or so. so the rest of your decrease in caused most likely by the weather getting colder, especially in the morning. now how much will the weather change affect you?? that depends. the longer the commute, the less the effect.

**edit** overfilling was an issue previously as it was not well known how much the mileage could be affected. considering the amount of "airplay" the overfilling issue has received here at PC, i doubt that is your issue. Toyota does monitor this website extensively and major concerns expressed by us are most definitely passed on to the dealers. my dealer takes it upon themselves to monitor this website as well.