Do I believe the evidence or the dealer?

An you've got me wondering who may have set up camp in my air filter . . .

You've GOT to post pictures.

 

what, like 90-weight gear grease?

(important)
I'm so amazed to read this thread. I don't have anything to contribute, but that I've also reflected upon many recurrences of the exact same symptoms you describe.

Here's what happens to me (not important, but detailed):

(1) take vehicle in for scheduled maintenance

(2) car gets shockingly worse gas mileage on the way out

I've encountered this numerous times, and every time I start thinking about Microsoft and the term "planned obsolescence" and it just drives me nuts but there's no hard evidence of anything other than a suspicion.

Moreover, I wouldn't -actually- suspect planned obsolescence (nobody would want their own brand vehicle (or any vehicle they service) to leave the shop with noticeably worse performance, ruling out all but the least deliberate of motive.

(important again)
I never could figure out what manner of accidental mis-calibration could cause such a dramatic drop. But then, my tires were always under-inflated coming out of the dealership.

It does seem strange to me, now that I'm seeing others experience it.

However, I'm a mathematician; many of you should have heard the phrase "correlation does not imply causation" and I'm sure plenty of people can describe dealer trips after which their mileage remains unchanged, and I can certainly describe times my mileage has taken a nose dive for reasons that are certainly NOT dealer-related.

~ dan ~

I conclude that if there's a causal relationship, it's a serious, but accidental, cause.

 

Yeah, that would really do it. I do not know if anyone has run a controlled experiment of seeing what the MPG changes are depending how what viscosity oils are put in. If someone has I would really like to know about it.

 

I also got poorer mileage after the 5000 mile dealer oil change on my 07, but put it down to the colder weather, since I do not keep very accurate mileage records. However, they did tell me that there was an upgrade to the computer that they did. I would guess that upgrade would apply to all 07's. I wonder if that could have caused your problem.

 

I have a 2007 and had it since Sept. I got a 5000 mile oil change at a local Quick Change; due to the fact that my dealership is a 40 min drive each way. i have not noticed a MPG drop due to this, but have due to the weather dropping. i will be blocking the grill later this week. if you use synthetic oil can you go to 7500 miles? i know the manual states 5000, but isn't that with regular oil? What are the benefits to using synthetic with such a small motor? if i do go back to reg oil, should I change it after 3000 miles or stay with 5000?

Thanks

 

I know for a regular vehicle with a full-time ICE (like my Mustang) it can benefit from ultra-light 0W-30 synthetics, so that you have oil pressure the instant you start cranking the engine.

I don't see how it would benefit the Prius, because it does all its stopping and starting after it's warmed up, when the oil is at its higher viscosity number.

~ dan ~

 

Whenever you talk about extended oil change intervals, get ready for a lot of comments on invalidating the warranty. It does not invalidate your warranty but you should know exactly what oil is being put into your car if you do so. 0W-30 or 5W-30 synthetic are the common choices for extended intervals. In very cold weather 0W-20 has been used by some.

Right now my program is to change the oil at 10,000 mile intervals. I use AMSOIL Synthetic 0W-30 and have the oil tested to ensure it is still in very good condition for extended intervals.

As a last note, The 2001 Prius (with the exact same engine as a 2007) has the Toyota Oil Change interval being 7500 miles, so what you are wanting to do was standard practice. The reason for the change to 5000 had nothing to do with the Prius, but due to problems Toyota had with big engines and bad oil and the Prius is an innocent victim of that.

If you want more info, search for posts by jayman. You do not need to change at 3000 miles, you are just wasting oil by doing that. For 5000 mile intervals, either synthetic or regular will work fine. It is the longer intervals (10,000 or more miles) that synthetic is the better choice.

 

That's amazing! My MPG's have dropped a little too, but I figured it was mostly due to tempreture. How do I check my air cabin filter?

I'll admit - I haven't searched yet, but I am about to!

Edit - using John's site - it's the filter right behind the glove box, no?

 

Thanks. I'm going to check mine today. I would have NEVER thought that would affect one's mileage so much.

 

I've got to ask. How could the cabin air filter affect MPG at all??

 

That's what I'm curious about the most. But it seems to have helped the OP. It was the only variable that was changed in the entire equation AFAIK...

 

I can't make any sense whatsoever out of this. Engine air filter, maybe. The cabin one? Uh....no.

?

 

The ONLY thing I could even think of or google would be if it was so clogged that it caused the AC to go into overdrive causing more engine use, etc.... But, for something so simple, why not check?

 

I change mine every few months. Made a slew of them out of furnace filters. We had some fires locally, and that filter really got dirty.

 

Rxmxsh - Your avatar just COMPLETELY FREAKED ME OUT.

It must have had EXACTLY its desired effect on me.

First, I thought there was a bug on my screen. But the slight discoloration of the transparency made me think somehow it was flexing my TFT. So I was kinda wigged out. Then I wondered why it wasn't moving away from the bottom-left corner of my screen. It was too weird to watch, so I decided to puff some air on it to remove it. When it didn't pop off, I went to put my finger on it and realized it was, in fact, just some genius' avatar.

Well played

I think once I determined it had to be a real bug, I never once went back to the concept that it could be on my screen. Maybe at 27 my eyes are starting to go; either way it's certain my brain is.

~ dan ~

 

:lol: That just made my night! lol - Believe me, you aren't the first person to try to kill the bug on their screen. ^_^ But you are the first that I know of to puff air at it!!

 

HAHA... Now let it just be understood that I'm going to get you... some time or another.

Be glad I'm sitting on an airplane waiting to taxi onto the runway. I couldn't possibly do anything about chasing you down, unless you happen to be in Chicago.



~ dan ~