Will MPG Increase with a New Hybrid Battery ,Transmission Fluid Flush, and Oil Change?

Forget modifications, except maybe for a block heater if you live where it is cold.

Just be sure that you have the equipment you are SUPPOSED to have.
LRR tires at the right pressure.
Using the right oil.
Brakes not dragging.

Oh......and ask the shop how old the 12 V battery IS.
If more than 5 years, replace it too.

 

I don't remember Gen3s having a lifetime MPG display. Instead, they have Trip A and Trip B MPG and distance. When an MPG is showing, look at the displayed Trip meter, that should be the distance over which that MPG applies.

But just erase and reset both of them, neither is any longer relevant. They are specific to the previous driver's driving patterns, trip or commute routes, and speeds. And to the prevailing weather during that time.

Reset them and start tracking your own personal MPG under your particular routes and driving patterns, that is what will matter. I use one trip meter for a whole fuel tank, the other for each day's MPG. The latter helps highlight how MPG starts out very lousy on a cold engine (not just a Prius, but any fossil fuel engine), then improves with warmup and distance.

A new traction battery may help, but fluid and filter changes shouldn't have a noticeable impact.

The most important "mods" are to driver behavior and style. Read up on how to drive for efficiency.

Also, check out these threads:
Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat
Why mileage gets worse in winter | PriusChat

There are plenty more threads available.

 

I was about to say, "Take it back!" till I saw that the battery is still under warranty. Whew!! Congrats.

On the transaxle fluid, it's due for a change. There is no such thing as a flush with the Prius transaxle. It's easier than changing the motor oil other than maybe the removal of some extra plastic.

 

I have no recollection of any such driving style memory in a Gen3 Prius.

 

Only 127k miles...that's great. I can't believe no one has suggested getting an OCC installed now while the engine is relatively young, before it causes issues with the EGR components...that's a pretty hot topic for the Gen 3s, especially the earlier ones. If I found a nice low mile 2010/11, I'd be all over that like white on rice.

 

The last time we suggest that to a new member, someone pointed out that we scared the new member away with the suggestion.

 

I have no grille blocking on mine and I’m running mid 40s on MPG with the winter temps. I keep the heat set on 70-72, fan no higher then half way. If outside temp is over 50, I turn the heat off all together. I thought about blocking the lower grille, but the “free” pipe insulation that I had was way too big in diameter, so I gave up on that. Drive it and enjoy it.

 

An OCC is AKA an oil catch can. It is spliced/installed into the line from the PCV valve to the intake manifold. It separates the liquid from the vapors that occur naturally inside the engine as byproducts of combustion. The liquid stays in the can to be drained at oil changes. The vapor passes thru the can to be burned thru the intake.

It is speculated that the liquid could be a factor in head gasket failure. The liquid will cause misfire as it gets aspirated into the cylinders. If you remove the throttle body from the intake manifold, you will see where the pool of crud collects. An oily sheen look is ok. A puddle is a bad thing.

 

Maybe not fuzzy logic, but the few times recently that I've done a complete 12 volt disconnect (for brake work), I'll notice the next two or three startups, there'll be an odd rev-up for the first 30 seconds or so. Like the car's testing and reestablishing some parameters.

Getting into Oil Catch Can typically requires some owner "involvement". There's various cans, from dirt-cheap to in the hundreds.

You are "messing" with the car; it technically voids pollution control specs, even though a properly installed OCC is keeping the environment cleaner. You might be failed if you have a regular emissions test, just because it's there. Dealership service departments might not be too impressed either, not sure.

Your current route between PCV valve and intake manifold is a short, 3/8" ID hose. With an OCC you introduce a LOT more hose, somewhat constrictive couplings, and the OCC itself, with baffles, filter material.

Most of us are doing this by seat-of-pants, but a mechanical engineer would likely have some reservations. It would take a mechanical engineer to fully understand the ramifications, and lieu, you just over-design, and closely monitor your wonder child.

Oh, and you have to empty it periodically, and once in a while maybe fully disassemble, clean out the innards.

All that said, if you're into DIY, I would go for it. I did. But be aware: it IS a bit of a rabbit hole. Just finding a suitable mounting location for starters, then how you're going to plumb it, hose diameters, couplings, and on and on.

If you want to see why you need it, take a look through the throttle body, below there you'll very likely see a little glistening pond. That's the gunk an effective OCC will catch, plus very likely more, the vapourized portion that didn't stop there, made it to the combustion chamber.

 

It' not an answer to the question but I want to tell my situation. I bought 2010 Prius on 235k with everything is original except the bumper. After that, I replaced trans-axle fluid and oil, and last week it had the second oil change with Mobil 1 Full S Extended High M. I also cleaned the air filter. As a result, the car, is now on 245k, started to accelerate faster than before and I can feel the increase of torque significantly. And it gets 43mpg in the temperature of 30s.