2010 Lower gas mileage after oil change

Although they may never admit to it, you may want to see if they actually used 0W-20 oil. Check out your invoice and see what it says...

Bryan

 

Definitely check the oil level ASAP. Even if it shows the proper level, I suggest you go back to the dealer, explain the situation, and make sure they check what viscosity oil was put into your car. If they inadvertently filled it with 20W50, your mileage would suffer (plus---it is not correct for your engine.

I hate to say this, but I don't trust ANYONE (including the dealer) regarding routine auto maintenance. I've been doing it myself for 40+yrs now, and figure I've saved about $25,000 and a lot of headaches. By the way, I'm just a "regular guy" as far as mechanical ability is concerned....but, I do know how to read and follow instructions. And, I've invested in around $500 in good quality tools.

 

This happened to me as well, but it was because they used the same bulk 5W-30 oil they use in all the other vehicles. They wouldn't admit it, but when I changed the oil with 0W-20 Mobil 1 oil, my mileage returned to normal.

 

If they did not put it on the invoice or a lazy tech just put in the regular without paying attention to what was on the request, how can you figure out if they screwed up? I am thinking mileage may work but my is not always the same bacause of very different trips. Is there an easy test from dip stick sample? Or some thing like that because as you say they will admit nothing!

 

I'm gonna ask them if I can be present when they are replacing the oil, because I can't trust what is written in the invoice.

 

Same here. Had the oil changed, mileage WAY down.... I specifically asked for the 0W-20, but I got it done right at the end of the day at the dealer.... I wonder if the tech used the wrong stuff.... Kind of frustrating to have to worry about the dang oil they put in the car.... I was probably one of if not the first Gen III to have the oil changed there....

 

You know, I was calling local dealers looking for the best price for the 5K oil change and one of the dealers didn't even know about the 0W20 oil... pretty scary

 

With all the money that is spent on a 'Green' car, if the dealers didn't know about the correct viscosity to use then they are morons...

 

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

 

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.

 

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.