MPG of 2015 candidate

hard to assume much with prius. was the car fully warmed up for your 5 mile drive? any hvac use?
what are you averaging in the 07?
chirping isn't normal, but idk what is causing it

 

then you should get that in a gen 3. but it's not necessarily the battery. 12v, tyres and pressure, air filter, throttle body, maf sensor, so many possibilities, or a little each of a few different things.
read up on the egr problem, idk if the 15 is affected because of upgraded pistons and rings.

 

Maybe a failing brake booster?

 

Yes, doc Prius will work, but you need to study and understand the readings before testing.
Lots of threads here. Or you could take it to a dealer for a battery health check with tech stream

 

So you want to jump out of an '07 generation 2 getting the mileage you're getting right now because you know that to get in a generation 3 with all the problems that generally go along with that setup for exactly what the sexy body lines? You better or you might want to rethink all that their generation 3 sitting around as paperweights and folks his yard strode out all over the US before you go spending all that money to fix up and make ready this generation 3 thing but you've got a lot of studying to do this is a bad move real bad even in California it's bad I mean what kind of deal are you going to get on this car with a near failing hybrid battery that's my imagined getting close to 10 years old and all that?. To me this is really kind of funny and I can't even imagine somebody really thinking that this is a thing to be doing I mean I could see possibly getting a payment on a generation 4 not for me but for everybody else I guess but backtracking like this and I don't think so You better study up real good and I'm assuming you're going to be keeping the generation 2. Because with the three in your stable you will need the two quite a bit back and forth to the parts store driving the car when the three won't run etc etc If you're getting rid of the two to have the three big mistake I hope hubby has a Honda or something.

 

The only significant revision with Gen 3 is piston rings (and associated pistons) revised to have more outward springiness, partway through model year 2014. See @rjparker ’s post regarding VIN’s.

EGR still clogs up, and head gasket failures still follow.

still, at 100k, if you get on the EGR cleaning, you’ll hopefully be ok.

 

Be sure you are looking at mpg on total miles or at least on a thousand or more trip meter miles.

A 12v battery so bad it becomes an energy suck costing 10 mpg is extremely rare because the 12v battery would totally fail first 99% of the time.

An hv battery causing it is common.

Likely a $2500 brake booster problem. However if it is not coding Toyota won’t replace it free. The free replacement expires in ten years from first use in your case.

So that car could have been delivered in Sept of 2014 limiting brake booster coverage time to Sept of 2024. If it was delivered in May of 2015 you would still have a year.

 

Warranty clock starts ticking at date of first purchase? Is that what you mean by “delivery”?

 

Yes

 

hard to say. mendel has an easy method of peeking inside a pipe to see how clogged it is.

 

E

I doubt the piston/ring revision reduces the 3rd gen EGR system’s propensity to carbon-clog much, if at all. I’m also convinced this carbon-clogging is the main reason the head gaskets are failing. Reliably.

with 100k you’re in “decent” shape; I would get on it soon. My 2 cents: thorough cleaning every 50k is the best, will keep the EGR flowing as designed.

The clogging introduces two factors: reduced flow, and asymmetrical reduction: the intake manifold’s EGR capillary channels tend to clog one after the other, starting with cylinder one, which is where the head gasket usually fails.

The asymmetrical clogging might also leave the cars computers in the dark about flow reduction: cylinder one can be completely starved while overall flow is still ok.

top two links in my signature have info; if viewing on a phone turn it landscape to see signatures.

 

About the only easy way is to to check the egr flow monitor that runs every drive cycle using Techstream or an app.

If the value is 18-21 kpa you have good flow and it is unlikely to be clogged. Bad flow will throw a P0401 code with the “EGR Monitor Bank 1” showing less than the minimum value. Partial clogging might read somewhere between 21 and the minimum.

Car Scanner app with Bluetooth obd2

 

Quote Mendel instead of me and he will get a notification

 

Pretty sure @bisco was referring to the check of the EGR pipe, the stainless steel piece between EGR valve and intake manifold. This’ll give you “some” idea of the overall state. See video #16 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

Again, see the top two links in my signature.