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  #961  
Old 04-09-2023, 09:57 PM
MikeD MikeD is online now
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Originally Posted by xcandrew View Post
Your third Gen Prius does have potential head gasket problems, with it being worse on the 2010-2012 in particular. The reason is that EGR system (EGR passages in intake manifold and the EGR cooler) gradually gets clogged, reducing flow. This increases combustion temperatures and eventually causes failure of the head gasket. More typically, it happens above 150K miles (sometimes way above), with fewer examples closer to 100K miles. There were changes to the piston and piston rings in 2014 and 2015 respectively that reduced blow-by and oil consumption and likely slowed the clogging of the EGR system. The fourth Gen Prius put the EGR beyond the catalytic converter, so it's pulling from cleaner exhaust and doesn't get clogged. Head gasket issues are not a problem in that generation (and presumably not in the new Gen 5).

There is some warning of EGR clogging and I suspect those that ignore check engine lights and don't keep up with maintenance are more likely to have earlier head gasket failure. The check engine light comes on if there is insufficient EGR flow. There was also a revised EGR valve (your 2013 might have it as production change, but I'm not looking up the date of change) at some point that was taken care of with an extended warranty. There are directions on Priuschat on how to clean your EGR cooler and intake manifold EGR passages, and I'd advise that you do it or pay to have it done if you want your 2013 to last. I did that work on my 2010 that I bought at 150K miles, and it never had head gasket issues (car was totaled in a caribou collision at 180K).

I actually don't consider a head gasket problem in a Prius to be disastrous (just like I don't consider it to be an issue in the Subarus that have it). On the one hand, 100K-150K is already an old car by most standards. It can be fixed for a few thousand dollars, or you can swap in the plentiful and therefore inexpensive Gen 4 engine for little money because they don't have head gasket problems and there's a large supply from crashed vehicles. A few thousand in repair, you still have reliable, still cheap to run transportation. I don't like thinking in terms of "more than the car is worth", instead preferring something like: when fixed, the car is otherwise in good shape to run another 150K, and that is worth $8K-$10K to me and the alternative, getting a new car is going to cost way more. When buying used, it can even be a negotiating tactic to get more money off something you want (people including me love their Subarus with repaired head gaskets). Anyway, it's nothing like the cost of replacing a battery in an EV - that easily goes into the definitely not worth it category. There's a famous used Tesla Model S that was blown up because there was no way the guy who bought it was willing to pay $22K to replace the battery.

https://www.theverge.com/2021/12/26/...on-repair-bill
There's a fellow on Prius Chat that put forth that theory about a clogged EGR system causing head gasket failure, without any proof other than the EGR system was clogged and thus must have caused the head gasket failure. He's very helpful though so I and others have only minimally pushed back on him. However, in this video from Gasket Masters, who do a lot of work on Prius's including lots of head gasket replacements, say it's thermal cycling that causes the failure. Makes sense because he says the non-hybrid Corolla, which has the same engine, doesn't have head gasket failure on near the same frequency as the Prius. The EGR system on these cars does clog and can cause driveability problems, so, even though its a major job to clean them, should be done eventually. I think that if you do a lot of city driving, you're a lot more at risk than if you drove mostly on the highway because the engine won't thermal cycle near as much. https://www.youtube.com/watch?v=gCIm4vndMrk
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  #962  
Old 04-09-2023, 10:39 PM
xcandrew xcandrew is offline
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There's a lot more than one person on Priuschat that thinks it's the Gen 3 EGR design. It isn't a problem on the Gen 4, which is the same engine, and it isn't a problem on the Gen 2, which is a very similar engine. That Toyota totally redesigned the EGR system for the Gen 4 points to the main problem (improvements during the Gen 3 production including pistons/rings, and EGR valve reduced, but didn't fix it entirely).

Last edited by xcandrew; 04-09-2023 at 10:42 PM.
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  #963  
Old 04-09-2023, 11:17 PM
MikeD MikeD is online now
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Originally Posted by xcandrew View Post
There's a lot more than one person on Priuschat that thinks it's the Gen 3 EGR design. It isn't a problem on the Gen 4, which is the same engine, and it isn't a problem on the Gen 2, which is a very similar engine. That Toyota totally redesigned the EGR system for the Gen 4 points to the main problem (improvements during the Gen 3 production including pistons/rings, and EGR valve reduced, but didn't fix it entirely).
It's not the same engine.
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  #964  
Old 04-09-2023, 11:32 PM
xcandrew xcandrew is offline
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Originally Posted by MikeD View Post
It's not the same engine.
Yes they are. Both Gen 3 and Gen 4 use the 2ZR-FXE.
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  #965  
Old 04-10-2023, 12:01 AM
MikeD MikeD is online now
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Originally Posted by xcandrew View Post
Yes they are. Both Gen 3 and Gen 4 use the 2ZR-FXE.
There's a thread on PC where someone tried swapping in a gen 4 engine and couldn't make it work (primarily cooling system changes). In that same thread was a quote by the OP that he saw a Gasket Masters video that they are replacing a lot of Gen 4 head gaskets too. If true more proof that the EGR system was not the cause. Furthermore you are ignoring the fact that the non-hybrid Corolla does not have a head gasket problem.

We a debate this forever but let's just agree to disagree.
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  #966  
Old 04-10-2023, 01:32 AM
xcandrew xcandrew is offline
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Agree to disagree? You aren't providing technical reasoning to support your position. Not sure why you care that much when you don't even know something basic like the Gen 3 and Gen 4 Prius engines being the same.

I still haven't seen a confirmed mention of a legit Gen 4 head gasket failure that was the engine's fault on Priuschat. There is an exhaust mounted heat exchanger that is used to improve warmup performance in the Gen 4. The earlier model year Gen 4s would have this part fail, and it would mimic a head gasket failure because there would be coolant coming out the exhaust. The part was revised, but if you read through the attached thread, MANY shops/people misdiagnosed this. The one Gen 4 head gasket replacement that I heard of was a misdiagnosis, which resulted in an unnecessary head gasket replacement. And that new head gasket failed because the coolant all leaked out the exhaust because the real problem wasn't fixed, and the engine overheated as a result. Here's the thread (Mukunda is the person I mentioned):

https://priuschat.com/threads/any-ge...gasket.230625/

If a shop is doing a lot of Gen 4 head gasket replacements that would be news to Priuschat. I haven't come across any legit failures, and doing searches, I only come up with Mukunda's case, which I'm pretty sure was a misdiagnosis.

Here's a site that collects and organizes NHTSA complaints. I see complaints about the heat exchanger on the exhaust in 2016, but no head gasket complaints in the Gen 4 (2016-2022). It also implies that most problems with the head gasket were the 2010 and 2011 models (though 2010 also had the most sales, covering both 2009 and 2010), with the problem gradually being mitigated by some of the things I mentioned (many intake manifold revisions, EGR valve redesign, piston and piston ring redesign). The 2010 and 2011 get "Avoid like the Plague", while 2012-2016 (including first year of Gen 4) get "Seal of Pretty Good" and "Seal of Awesome" (2017+).

https://www.carcomplaints.com/Toyota/Prius/

There have been a lot of successful Gen 4 engine swaps into the Gen 3 Prius and Prius V as far back as 2018. If someone isn't successful in the swap, they didn't read the right threads and youtube videos. The details are all there on Priuschat - I read the early ones as they happened. It's not Toyota authorized so there isn't one authorized place to go for instructions. That's why some swaps have been messed up, not that it's a substantially different engine or that difficult to do.

The Gen 3 and Gen 4 Priuses have the same engine with the same name 2ZR-FXE. The non-hybrid Corolla engine is different enough it has a different name: 2ZR-FE. The 2ZR-FXE in the Prius is Atkinson cycle with a 13:1 compression ratio. The 2ZR-FE in the Corolla is Otto cycle with a 10:1 compression ratio. The Atkinson vs. Otto cycle is a huge difference in how the engines work. Why would the Corolla engine be more relevant to Gen 3 head gasket failure discussions than the Gen 4 Prius engine?

That's not to say there aren't changes to things attached to the engine. Some details are different between the 2ZR-FXEs that are in the Gen 3 and Gen 4 Priuses. The rerouted EGR system with the larger cooler for one. There is also a water jacket insert to change the distribution of heat along the cylinder bores which likely helps the head gasket reliability. But this isn't in the Corolla engine. Here's a good listing of the differences between the Gen 3 and Gen 4 engine. Notice the figures say, "Current Prius 2ZR-FXE" and "New Prius 2ZR-FXE" to distinguish between the Gen 3 and Gen 4, meaning same engine with a few different things bolted on.

https://www.marklines.com/en/report_all/rep1473_201602

The EGR cooler of a Gen 4 Prius with 360K miles on it was removed for inspection, and it was very clean and didn't need cleaning. A Gen 3's EGR cooler would be pretty plugged up well at half that mileage (I did the EGR cooler cleaning on my 2010 myself). That's a decent gain for moving the EGR input from before catalytic converter to after on the exhaust.
https://priuschat.com/threads/gen-4-...-miles.236530/

Last edited by xcandrew; 04-10-2023 at 04:05 AM. Reason: added last paragraph
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  #967  
Old 04-10-2023, 05:57 AM
MikeD MikeD is online now
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Blah blah blah. What's the mechanism for an EGR system causing head gasket failure? Does the engine knock? Overheat? NO. Weak argument supported by no data. Why do you believe some dude on PC over a master mechanic (GM) that has repaired and seen hundreds of these failures? Sorry not me. GM says the EGR system doesn't cause head gasket failure.

https://www.youtube.com/shorts/JL3hIUro7SM

Last edited by MikeD; 04-10-2023 at 11:07 AM.
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  #968  
Old 04-10-2023, 10:42 AM
pasadena pasadena is offline
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Quote:
Originally Posted by xcandrew View Post

About the million-mile-Tesla, you say "That battery pack has lasted." That is not true. It had the battery pack replaced at least two times (so three or more batteries to hit one million) and was on its eighth motor unit.
333,000 miles per pack. Just as Tesla states. 300-500k miles. Putting on so many miles, i'm guessing he always supercharges which shortens battery life.

Most ev owners charge at home and don't fully discharge on a regular basis. That extends battery life significantly.

Battery tech and chemistry is moving on. Get off the Toyota kool-aid. The only reason they are doing it is because they guessed wrong on hybrids and hydrogen and the entire company might not even exist in 10 years because of it.
It's unfortunate, and they are so far behind ev's the amount of scrambling in the last 3 years is amazing to see from such a deliberate and conservative company.

They hybrid reasoning makes sense, but Toyota was spouting it as the future when Aoki Toyoda was in charge and put them in the hole. He resigned so they could actually move forward with ev's and try to compete.

That half ass bz4x is what Toyota thought of ev's. TGNAe scrapped completely and new ev platform being developed. The pace they are moving is incredible.
That's a good desperation. If any company can do it, Toyota is one that can.
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  #969  
Old 04-10-2023, 11:19 PM
xcandrew xcandrew is offline
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Quote:
Originally Posted by MikeD View Post
Blah blah blah. What's the mechanism for an EGR system causing head gasket failure? Does the engine knock? Overheat? NO. Weak argument supported by no data. Why do you believe some dude on PC over a master mechanic (GM) that has repaired and seen hundreds of these failures? Sorry not me. GM says the EGR system doesn't cause head gasket failure.

https://www.youtube.com/shorts/JL3hIUro7SM
Thanks for the link. First one I've seen, so that's interesting. I'm not doing this to be argumentative with you. A used, high mileage (because I don't spend more than $10K for cars) Gen 4 Prius is something I've had in mind as possible future purchase.

He doesn't say what the mileage is, which is important. In the comments of that, there's a taxi operator with 35 of those Priuses, with up to 600k kilometers, and he's only had to replace head gaskets in one. Also, I re-searched the Priuschat Gen 4 subforums for "high mileage", and none of them reported head gasket issues even up to 280K miles. Seems like a big improvement over the Gen 3 to me.

I watched his other video with his guess of why the Prius head gaskets fail, and I don't really buy it any more than the other explanations I'd read. He's saying the head gaskets fail because they are flattening due to the increased number of heat cycles. I'd assume, but maybe I'm wrong, that multi-layer-steel head gaskets were designed to operate below the fatigue limit of the steel used, so the number of cycles shouldn't matter. Also, hybrid engines are just not cooling off much when they cycle off, which is typically no more than the length of a red light at the long end.
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  #970  
Old 04-11-2023, 12:24 AM
xcandrew xcandrew is offline
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Originally Posted by pasadena View Post
333,000 miles per pack. Just as Tesla states. 300-500k miles. Putting on so many miles, i'm guessing he always supercharges which shortens battery life.

Most ev owners charge at home and don't fully discharge on a regular basis. That extends battery life significantly.

Battery tech and chemistry is moving on. Get off the Toyota kool-aid. The only reason they are doing it is because they guessed wrong on hybrids and hydrogen and the entire company might not even exist in 10 years because of it.
It's unfortunate, and they are so far behind ev's the amount of scrambling in the last 3 years is amazing to see from such a deliberate and conservative company.

They hybrid reasoning makes sense, but Toyota was spouting it as the future when Aoki Toyoda was in charge and put them in the hole. He resigned so they could actually move forward with ev's and try to compete.

That half ass bz4x is what Toyota thought of ev's. TGNAe scrapped completely and new ev platform being developed. The pace they are moving is incredible.
That's a good desperation. If any company can do it, Toyota is one that can.
Just wanted to get that straight because you said it was one battery, not three. If you are the new EV car owner, you've already got your money's worth, and you probably don't care. I feel like I'm repeating myself too much already, but I'm writing as an advocate for sub-$10K used cars because many people need them. I'm still wondering how cheap, reliable transportation can still exist in the future when the used cars in that price range are mostly EVs past warranty with unknown battery health.
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  #971  
Old 04-11-2023, 07:38 AM
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paredown paredown is offline
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If someone is on the fence about whether or not to purchase an EV right now, Treasury has released guidance that the new rules on American-made batteries does not take effect until 4/18.

So if you purchased a vehicle between now and the 18th with a 'non-compliant' battery, you will still qualify for the EV rebate:
https://home.treasury.gov/news/press-releases/jy1379
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  #972  
Old 04-11-2023, 11:41 AM
robt57 robt57 is offline
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Originally Posted by paredown View Post
If someone is on the fence about whether or not to purchase an EV right now, Treasury has released guidance that the new rules on American-made batteries does not take effect until 4/18.

So if you purchased a vehicle between now and the 18th with a 'non-compliant' battery, you will still qualify for the EV rebate:
https://home.treasury.gov/news/press-releases/jy1379
As Tesla Starts a huge Battery building facility in CNH. But then again, Telsa keeps dropping prices and way over numbers sold to qualify for US Fed Tax credit I guess..
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  #973  
Old 04-11-2023, 12:33 PM
pasadena pasadena is offline
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Originally Posted by xcandrew View Post
Just wanted to get that straight because you said it was one battery, not three. If you are the new EV car owner, you've already got your money's worth, and you probably don't care. I feel like I'm repeating myself too much already, but I'm writing as an advocate for sub-$10K used cars because many people need them. I'm still wondering how cheap, reliable transportation can still exist in the future when the used cars in that price range are mostly EVs past warranty with unknown battery health.
Like used cars now that are past warranty with unknown engine and trans health?

Don't know if you've looked at used car prices but $10k won't buy much, ice ev or hybrid.
So instead of 300-350mi range, that $10k buyer will get maybe 150-200mi and live with battery degredation - and you know what? Maybe for $10k, that is totally fine for however many years they keep it.

There are plenty of ice cars around and will still be around for decades. The amount of $10k used ice cars available will increase in the next decade, not decrease. And when the used market eventually dries up, there will be a lot of ev's on the secondary market at that price.

plug in hybrids like the prius prime are good half-steps for people that travel long distances daily not near developed charging infrastructure.
But that's all they are.

Most people drive under 35mi a day. A Prius Prime is only $4k less than a full ev Tesla 3. If you qualify for incentives, a Tesla 3 is $34k. Doesn't make sense to get a hybrid for the majority of people.
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  #974  
Old 04-11-2023, 02:22 PM
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kppolich kppolich is online now
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First longer road trip in my '21 Tesla Model 3 long range this past weekend.

Trip length: 360 miles each way, 720mi round trip

Previously in my '13 Subaru Impreza I could make the entire trip without stopping for gas. Not that we ever did as we always get out halfway to stretch, let the dog out, etc.

Tesla: Left our house with 97% charge, arrived 2.5 hours later at our Supercharger with 27% remaining. $14 dollars and 15 minutes later we left with 85% charge and drove 2 more hours to our final destination with 23% battery remaining.

I plugged in at our final destination (120v/15A) outlet and we were back to 100% day before we had to leave to return.

Trip home:
Left with 100%, drove 2 hours and arrived at Supercharger (2 other cars there this time vs. 0 the first time) charged from 40% to 80% and left for ~$10. Drove the final 2.5 hours and arrived home with 25% remaining.

Overall, we are stopping for 10-15 minutes anyway so whats the big deal. Yes, the superchargers were farther away from the grocery store they were at, but I don't mind walking into the store to throw some trash away, use the restroom, etc.

The supercharger was fast, but not even the fastest versions out there. I was charging at 144kW or 586mi/hr.
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  #975  
Old 04-11-2023, 02:44 PM
benb benb is offline
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LOL my 2013 Outback only makes 360 miles on a route that's favorable and if I keep the speed below 70mph the whole way. And my back will probably convince me to stop earlier. Nothing is really wrong with my back except that seat.

My biggest concern with the current EVs is how many still don't have a heat pump.. a lot of the EVs that look fine in the summer look like they might be annoying for ski/snowboard trips in the winter. Our typical trip is about 200 miles, it sounds like there are a whole bunch that are well above that on a 65 degree day but drop below 200 miles when the temperature is below freezing. If I had to really get a new car it'd probably be the deciding factor pushing me into a Tesla.
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