My 2008 Prius has 319k and I bought It last year with exactly 300k and did all maintenance. Did plugs, transmission fluid, all steering and suspension work and replaced the Inverter pump (oem). Today I was on the highway and went to accelerate and the Prius refused. Engine revved (I think) but wasn't speeding up. The whole time I'm waiting for a error light to come on, but none did. I scanned with my high end scanner when I got home and no codes for the engine or battery system. I had just filled up last night. I do drive the car aggressively, but today Is the only time It's had a problem. I had It floored and It seemed to actually be losing speed quicker that way. I limped It home and checked all the fluids and they were all fine. After I checked everything, I went for a drive and still the same thing. Above 50 mph If I floor It, the engine starts to sputter and then clear Itself up and then sputter again. Still no lights or codes. Eventually It'll stop picking up speed until you very gently ease Into the gas. It feels like a misfire, but that should set a code. It was 80 degrees and I did have the ac on and the battery charge was full blue bars when all this started. Seriously zero warning lights or codes stored.
319k miles. I would say this is a pretty worn engine. As these cars age, you'll find problems with everything. Fuel pump, injectors, vvti solenoid/filter, throttle body. You name it, it'll go bad.
That's way more true with Gen3 Prius than Gen2 Prius... The Gen2 Prius has an exceptional reliability record even at 300K miles.
Gen 2 doesn't have a headgasket/EGR issue but all the other underlying issues are still there. If the cars are maintained properly and meticulously, they should be very reliable. Good example is Mendel's 2010, 12 years old Gen 3 and still like new.
Gen2 doesn't have head gaskets that consistently fail before 200K miles, as well as piston ring failure due to bad design, as well as a hybrid braking system with way more potential points of failure, as well as oil filter design so incompetent that mechanics use an impact driver to change the oil filter which destroys things, as well as a catalytic converter that if stolen can often lead to all your engine coolant draining out. I could go on and on about how Gen3 was a massive step backwards in terms of reliability compared to Gen2 and Gen4.
1. From what I've experienced with Gen 2, which is most of my collection, the piston rings are not that great. They burn oil like any other Gen 3. 2. Hybrid braking issue - both generations have problems with their accumulator/actuators 3. Oil filter - Nearly all the new models have the cartridge type oil filter, bad mechanics not knowing how to tighten/loosen them doesn't really make them a bad design. 4. Catalytic converter getting stolen can cause lots of potential problems with any car. Thieves will cut everything that's in the way to get what they want. This does not mean it was a bad design vs the earlier generation. If anything the argument should be better for Gen 3 as those catalytic converters are not even wanted by thieves.
Gen 2's hybrid braking system is also pretty weird, just a different weird. They did Gen 2 a whole different way than Gen 1, and then Gen 3 went back to the Gen 1 approach but with some improvements. Gen 4 further split the system up in in interesting ways. Gen 2 is the only one of all the generations that's fully brake-by-wire, with no hydraulic boost in the fail-safe operation. So to make up for that, they gave it a box of capacitors, to make it less likely to lose electric power. So it really is kind of weird.
It was definitely a bad design which is why they discontinued its use... I did oil changes on Gen2 and Gen4 and Prius C and never knew they changed oil filters on Gen3. It was a bad day when I found out too! The specific design flaw is that as soon as a minimum wage worker at an oil change place can't get the filter off and resorts to an impact driver they tend to assume that's how it's suppose to be done. Add to that the fact that Toyota didn't use a standard socket size and it's a millimeter or so smaller, meaning the store bought oil filter socket slips when it's jammed. So many buy the proprietary socket from Toyota instead, increasing costs again. Even dumber, the filter is way less material than standard yet costs twice as much as standard. It was a classic goat rodeo in the outcome of that "advancement."
Your argument about the oil filter is not very valid. If a minimum wage worker does the service, he still needs to be trained properly in doing it. And the tool needed to do the change, a shop should have it or a car owner would need to buy it once for their car. This is no way is a design problem as it is a better product than the spin on filters the earlier generation had where it can fall off if not installed or tighten correctly. I don’t think you can argue one generation is better than the other because of oil filter design
