3.4L TTV6 Engine Failures (V35A-FTS)

sl0519

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2UR is still in service for the Century sedan and allegedly the IS500's life cycle has been extended. The TTV8 is debuting in the new GR GT/LFR.

It's funny we are hearing these rumors ever since Covid 19 don't you guys think they are trolling us at this point.
 
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Seems like your prayers have been answered the new i4 engines are developed with gr

Seems like it. 400 horsepower 2.0L 4-cylinder is absolutely crazy. This eclipses the 187.5 hp/L specific output of the GR Corolla's G16E-GTS. I wonder if this new 4-cylinder engine shares any similarity with that.

Also at this point, I'm praying they add another 2 cylinders.
 

Ali Manai

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Seems like it. 400 horsepower 2.0L 4-cylinder is absolutely crazy. This eclipses the 187.5 hp/L specific output of the GR Corolla's G16E-GTS. I wonder if this new 4-cylinder engine shares any similarity with that.

Also at this point, I'm praying they add another 2 cylinders.
Not to mention the 600bhp version
 

Flagship1

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@Gecko seems a lot of owners around the interwebs have similar threads going. Tundra due to sheer volume and community I linked seem to be having a field day with the recall, pictures and video documentation included.

I do wonder what kind of fix this will turn out to be. Seems like there is no easy way to inspect debris. They can run mass oil analysis, but that would require a series of reports over a couple ocis to figure out. They seemed to narrow down the ranged to non hybrids and select cutoff for production dates.
 

Gecko

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I've been following this closely over the last few days and I think this situation looks pretty bad for Toyota at the moment though I am glad they've issued the recall and are working with owners.

The recall covers 2022 and 2023 Tundra and LX 600 gas-only models right now, and excludes hybrids. I don't know why because the Sequoia and Tundra iFORCE MAX models have both had engine failures. One theory I read was that Toyota has more data on the 2022 and 2023 gas models by volume, so the first stage of the recall is for those models but others can be added anytime. It seems like it's only a matter of time before the 2024s and hybrids are added as more are sold and the miles increase.

The theory about regular gas vs. premium gas has been debunked. Same for oil change intervals.

The theory that one random guy on the engine assembly line in Alabama wasn't adequately washing debris from the engine components during installation also seems to be disproven since this is happening to LXs, which are built at Tahara. The LS is a much lower volume vehicle, but it has also had engine failure issues and is also built at Tahara. If machining debris is the issue, it's a problem with Toyota's production process, seemingly not one specific case of human error, as it's occurring at two different plants with four different models.

A few technicians are starting to speak out online, and whether that's for attention or just to help concerned owners, their theories seem closer to making sense IMO.

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The Tundra has had its fair share of issues but they aren't all related to this (For example, the turbo wastegates early in production were something totally different), but owners hearing knocking or stalling has often been a documented precursor to the engine failure, and that's been going on for two years with Toyota replacing various parts or rebuilding engines for impacted customers. This has been going on so long that the "machining debris" explanation just doesn't make sense to me -- that would have been easy to fix when the issue first popped up.

There have been reports of LSs, LXs, Tundras and Sequoias with spun bearings and the bottom end of the engine is burned and starved for oil. Whatever the cause might be, to me this is looking more like a potential design, process, or material defect than a production issue with debris. The Tundra being the highest volume vehicle to use this engine means it's taking the brunt of the bad PR, but if I owned an LX, Sequoia, GX 550 or LS 500 with the V35A, I'd be watching this issue to see what happens and what the remedy might be.

I have faith that Toyota will fix this for current and future owners, but it makes me wonder if a revised V35A could be on the horizon once the issue is diagnosed.
 

qtb007

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There have been reports of LSs, LXs, Tundras and Sequoias with spun bearings and the bottom end of the engine is burned and starved for oil. Whatever the cause might be, to me this is looking more like a potential design, process, or material defect than a production issue with debris.
I wouldn't bet on that. When a machining process is developed, they will spec the same tools, cutting speeds/feeds, deburring, washing, etc and have everyone that builds that particular item use the same process.

An example of this would be a tool that normally makes a small, detached chip when the tool is new. When that tool gets some age to it, the chip starts to change shape or doesn't fully detach or rolls over a burr. So the washing process that cleaned out chips well on a new tool doesn't work as well when the tool reaches end of life. The fix could be limiting the tool counter from 5000 cuts down to 4000 cuts and the recall impacts every engine built when the cut number was beyond 4000. That original tool life would have been set to 5000 at both facilities that build the engine. That would be a production issue that hits both places.

JMO, but I've been in manufacturing as an engineer for nearly 20 years. I've seen a bunch in my career and unless someone has real intimate knowledge of the actual point of cause and root cause, it is all speculation. We only truly know that Toyota says there are chips that weren't getting washed out. Whatever some youtube "expert" puts in his flashy video is speculation at best until someone with actual knowledge puts it out there. The mechanics, IMO, are the worst about this speculation. Dunning Kruger in full effect there. They see the failed engines but they are completely ignorant of the *actual* root cause that led to the failure.
 

Gecko

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I wouldn't bet on that. When a machining process is developed, they will spec the same tools, cutting speeds/feeds, deburring, washing, etc and have everyone that builds that particular item use the same process.

Can you elaborate more on this? To me, the fact that this is happening across different models built in different factories seems to indicate that there is a problem with the design itself, the manufacturing or assembly process, or the materials being used... and not a one-off careless person on one assembly line (as was a previous theory). If that is not the case, you know more about this world, so I would appreciate the opportunity to learn 🙂.

JMO, but I've been in manufacturing as an engineer for nearly 20 years. I've seen a bunch in my career and unless someone has real intimate knowledge of the actual point of cause and root cause, it is all speculation. We only truly know that Toyota says there are chips that weren't getting washed out. Whatever some youtube "expert" puts in his flashy video is speculation at best until someone with actual knowledge puts it out there. The mechanics, IMO, are the worst about this speculation. Dunning Kruger in full effect there. They see the failed engines but they are completely ignorant of the *actual* root cause that led to the failure.

Agreed that it's all speculation at this point but I also doubt that we will ever get the full story from Toyota. I would be surprised if they ever release more detail than what has already been shared, so as their diagnostic process continues, only Toyota will know what is found.

I'm not faulting Toyota alone for this, but it's not uncommon for manufacturers to open a recall or TSIB under a name or explanation that's quite different from the underlying problem. The beauty of PR. Without much more data from Toyota, I think hearing from techs who have done the tear downs and rebuilds is as much input as we've got but more (official) data is always better. Most of these engine failures have been handled by certified master techs and having worked in dealerships with those folks before, I'm inclined to listen to their opinions and experience.
 
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Flagship1

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The last failure of this sorts (part that was difficult to easily access and examine) was back in 2017-2018 and the rollout of the UA80.

Toyota issued a TSB, followed by a Customer Warranty Enhancement program which I think what a tech posted above was alluding to as a possible resolution toyota may take. The issue there was that while toyota was able to narrow down the production units, some failed transmission owners were not included and as a result you got screwed due to no fault of your own.

While mechanics are not the ones responsible for root cause failure analysis, they are the first ones in field exposed to the issue and the ones respnsible for implementing the fix. In addition if they have some years under their belt, somewhat know what to expect with toyota approach to problem resolution.

How they intend to access and examine bearings are going to be the million dollar question? This may just end up as a wait and watch type of scenario like the ua80, with the only effected units getting short blocks, and true fix will be to only purchase once toyota has introduced at the production level a v35 offering.
 
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qtb007

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Can you elaborate more on this? To me, the fact that this is happening across different models built in different factories seems to indicate that there is a problem with the design itself, the manufacturing or assembly process, or the materials being used... and not a one-off careless person on one assembly line (as was a previous theory). If that is not the case, you know more about this world, so I would appreciate the opportunity to learn 🙂.
When a manufacturer plans on building a new product, they determine which plants have the space, manpower, etc that can generically be called "capacity". They'll assign X number of units to one plant and Y to another. As far as I'm aware, all the V35 engines come out of Tahara and Alabama. Engine plant and vehicle plant aren't always the same. Ideally, the machines, tools, posture, manufacturing specs, etc are all common between the plants by default. Then each plant takes that plan and massages it as needed to make it work in their space/manpower/logistics/etc. The ideal condition is that it is same same same because everything is cheaper when one design can work multiple places. So each plant will order the same spec of machine, use the same tools, run them the same way. This is great for flexibility, as we've seen with COVID, that volume can shift around from plant to plant. It is usually a big improvement to quality, too, because instead of investing a bunch of time to make the same basic product in 5 different ways in 5 different places, that 1 method is used 5 different places and more time is spent studying the depth of the process rather than solving the same manufacturing process challenges 5 different ways. Find 1 way to skin the cat and get really good at doing it that way. That said, when something gets missed, which something always does, it is a problem across multiple facilities because they all have the same process design.

A very important detail, IMO, is that a spun crank bearing caused by contamination doesn't necessarily look any different than a spun crank bearing caused by the wrong size of bearing selected. Not enough clearance between the crank and the bearing means material starts getting removed. Debris and heat start building up and just a mess is left. A mechanic is goin to pull the crank caps off, determine what can and cannot be reused, and send it back to the manufacturer. He usually doesn't know exactly why it spun but just that it did. Contamination? Clearance? Misshaped? He doesn't have the tools to investigate. The part goes back to the OEM and the mechanic repairs the broken vehicle. The engineers at the OEM will start dissecting the failure and are doing material analysis to see if there is anything unexpected. Was the lubrication system working correctly? Was the oil in good condition? If the bearing is made from material A and the crank is made of material B but they find material C as well, that means the debris was foreign. Was it dropped in there during assembly or was it flushed in there during running? So they start checking processes. Is this material found somewhere nearby in assembly? Does it match the material for anything in the oil circuit? We're now 3 or 4 degrees past where the mechanics saw the problem.
 
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I just refuse to believe that a company like Toyota would allow "engine debris" to be within the block. This has to be a design flaw.
 

Flagship1

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fwiw the hybrid short block and non hybrid have different part numbers. Besides the numerical difference is their anything physically different?
 

Demetrius

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Are LC300s seeing the same issues in decent numbers? I would expect so, but the outcry just doesn't seem to be as loud from our Middle Eastern and Aussie brethren. Would be shocked--puzzled really, if those aren't affect.
 

NomadDan

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The V35 has been in production in the Lexus LS for years before going mainstream in the BOF products. Did these issues also exist back when the LS was the sole V35 application? I don’t recall hearing about V35 failures in the LS, but perhaps that’s just due to the low volume.