After First Oil Change Mileage Seems Lower

Perhaps suggest to him to put it in writing and drop a hint that you will be getting the existing oil analysed. They might read between the lines and get something sorted for you asap?

 

My unscientific and uneducated experience is that I can tell immediately when the wrong oil is used. As soon as I got in my car after 5w30 was used by mistake, I noticed it sounded quieter and was more hesitant or resistant under higher acceleration as well as the top end fuel economy being reduced.

When the dealers agreed to correct the oil with 0w20 I noticed as soon as the engine fired up. It wasn't as smooth as 5w30 but definitely the same as what I was familiar with previously. Acceleration was immediately back to normal, as was top end fuel economy.

Perhaps the rules of 'breaking in' a synthetic oil don't apply to the water like, super thin (and expensive) 0w20?

 

When I asked the dealer what oil they use for Prius, they said 5W30, I said that in the manual it states 0W20, they said like something, yes you can also use that oil. I asked how much they charge for 5W30 oil, they said 89 € for 4,2 liters. I said can I bring my own oil, they said no problem, case closed.
Bought 8 liters (2 oil changes) of Mobil 1 0w20 for 100 € on ebay.de, couldn't find it cheaper here in Europe, they were insisting that I fill additional 2 dcl of oil, but I checked the dip stick and it was already just below max level, so I didn't.

When I bought car (used) it was (over)filled with 5W40, fuel economy in last summer was around 5 % off if I compare it with this summer. I also noticed that with 0W20 engine is not running as smooth as before.

 

yes the manual say you can use other oils
p546 0-20 is best fuel economy and if it's not available use5w-30 but use ow-20 at next oil change

clearly toyota recomend 0w-20first and others as last resort

 

In many markets there are incentives for the Prius because of its fabulous fuel economy and low emissions. If the 5w30 oil is used the Prius will not comply with the great mpg figures and thus its official ratings will be higher and it would be ineligible for these incentives.Without these incentives I fear Toyota wouldn't sell as many Prii.

Toyota can't have their cake and eat it.

 

Whenever I go to the dealer I always get the feeling they tell me have a seat and pay no attention to the man behind the curtain. The car will magically get done.

In the waiting room I'm not allowed to see the car and I can't see they actually used the correct oil or really changed the oil filter. It's just an uneasy feeling for me when someone tells me it's a free service.

After that first visit I decided to do my own oil.