Anyone noticed MPG difference after oil change?

Earlier this month I got my oil change at the dealership (under the two year service contract). The scangaugeII registered 60 mpg for that trip starting from a cold start from my home to the dealership that morning. It took 1.5 hours to get my car services and I was out by 8:30 am. With the Prius already warmed up , I drove the Prius another 12 miles or so to work( DARCARS of Silver Spring off Cherryhill Rd in MD to downtown Bethesda,MD). The weather was dry and warm and my route was hilly with the heavy traffic moving at around 25mph to 38mph on a black asphalt surface. Usually even with a pre-warmed up Prius using every hypermiling trick I know the Prius' MPG usually maxs out at about 83 mpg for trips over 11 miles under optimum conditions. However, this time and this time only the ScangaugeII AVG xgauge indicated that the Prius had achieved 151 mpg on that 12 mile trip! I double checked the ScangaugeII and it seemed to be working okay. ...very strange The next day (3/10/12) I filled up my tank with 9.785 gallons of gas after travelling over 594.8 miles (60.7 mpg calculated, MFD=64.3 mpg). Temperatures have increased to 60F in the mornings and up to 80F in the afternoon so I've taken off the grill blocking ... my overall MFD has jumped to 68 mpg since then but I was thinking it was due to the with warmer temperatures and not to the oil change... could be wrong though.

 

The only effect an oil change would have is if the car is left on while it is sitting around on the lot.

 

If the level is too high before or after it would change the mpg.Other then that I dont see how it would make much of a difference.

 

I've noticed improvements with all the cars that I've owned. The same is true after washing my car: It runs smoother, has more pep, and generally feels better to drive. The technical term for this is the "placebo effect".

Tom

 

That's exactly what you asked. You just don't like my answer.

Tom

 

Having a pre-warmed up engine can push the Prius's FE up very high since it eliminates a big energy hit a Prius has from initially warming up the catalytic converters. However, nothing beats going one way downhill!

 

Warm dry weather is pure love for a Prius.

It is a piece of cake to get 50 mpg calculated
when its 70 degrees and blue skies.

Even my wife who drives with no care for mpg's
gets over 50 mpg during the summer....

 

Re: Anyone noticed MPG difference after oil change?

Nope.

 

I changed my oil on my Prius at 1k, 5k, 10k & 15k miles. I looked back & saw no significant change in mpg after each change. I just did the 15k mile oil change the other day though since Toyota doesn't change it as often as I like to have it done.

 

Been a while since you posted the question, but I went looking before I posted the same question. I had my first service two tanks ago. My very stable 47 mpg has dropped 2 mpg on average. No obvious change except the service. Was wondering if anyone else had seen that?

 

I had my fuel mileage drop to the 38 to 48 mpg range after having the oil changed at a dealer. My note on fuelly.com commented that I wasn't for sure if they used the right weight because mileage dropped immediately. This was December 2012 through January. After having the oil changed at a dealer I trust, the mileage is back. Can't say 100% for sure the dealer was to blame because temperatures dropped, I did some long distance holiday driving. Bottom line is I'm never using that dealer again. Dealer2 seems to be trustworthy. I'll just go with what works.

 

YES, YES, YES. After my last oil change, my MPG has dropped. Before the service, I was getting 48 Highway, 52 city no matter the time of year with AC running or heat running. Now I get 45 Highway and 42 city. I've had the Prius for over 2 years and I know how to drive it for the best MPG, but something is wrong. I took it back. They cleaned the injectors and the throttle body. I thought it was fixed because the MPG improved on the drive home, but after that day, the MPG steadily got worse. I find it funny that I used to get better MPG for city driving. Now, I get better MPG on the highway. This is not the way the Prius is supposed to perform.

 

YES, YES, YES. After my last oil change, my MPG has dropped. Before the service, I was getting 48 Highway, 52 city no matter the time of year with AC running or heat running. Now I get 45 Highway and 42 city. I've had the Prius for over 2 years and I know how to drive it for the best MPG, but something is wrong. I took it back. They cleaned the injectors and the throttle body. I thought it was fixed because the MPG improved on the drive home, but after that day, the MPG steadily got worse. I find it funny that I used to get better MPG for city driving. Now, I get better MPG on the highway. This is not the way the Prius is supposed to perform.

I want to add that I have 75,500 miles on my 2010 Prius and I've always had it serviced at the dealership.

 

You might check with "Bob is the oil guy" site. I have not done any engine oil analysis, just transmission oil, but I would offer some speculation:

• loss of oil - with less oil, it warms up faster, the viscosity thins out giving lower 'stirring losses'
• shear down - as the engine oil ages, the mechanical stresses rip some of the longer chains, especially the viscosity additives, resulting in lower 'stirring losses'

I've seen no significant loss of mileage after an engine oil change. But then I've learned how to change my own oil.

Bob Wilson

 

i have seen dramtic change..........i changed the oil myself because the wrong oil was put in orignally by toyota...i put in recommended 0-20 oil and noticed a difference straight away
so if a garage does it you may notice a change because they put wrong oil in...

but if you change using same oil tha was put in originally..you probably ont notice much

 

I would think New 0-20w oil change would only help the MPG because of less friction ...........................

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Me neither.