I have a 2023 Sequoia and it has been a trailering beast, love it. Being a retired Professional Engineer, here is my theory on engine failures , maybe Nate will chime in and agree. Since we have a new "caged" main bearing assembly, unlike the reliable old single bearing cap design, I believe we have a resonate frequency (or natural harmonic issue, which is causing the bearings to fail. The hybrids have a large DC motor to dampen the frequency, thus the reason the hybrids seem immune to failure. I wonder if the Toyota engineers have considered this?
3.4L Toyota motor failure cause - something no one has mentioned
Started by OldPEguy ยท November 7, 2025 at 3:36 AM414
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OldPEguy
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TheCarGuy
Nov 8, 2025 at 4:37 PM
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I used to think it might be due to the same thing but we have been seeing hybrids fail as well.
I think the most frustrating thing for everyone is that there doesn't seem to be a pattern. Some people make it 100k miles and still have a failure, others only 1000 miles...hybrids and non-hybrids fail but they sell a lot fewer hybrids so naturally the numbers will be lower. I do think there is something to the torque distribution and the hybrid taking the brunt of that low end torque on every stop/start....but they still fail nonetheless.
Many companies have been using that caged system for years without issue, but I suppose there might still be some problem with Toyota's design of it. I believe they are also using dissimilar metals for the cage vs. the block, you have to wonder if that is helping cause this problem too?
At this point....I just hope they get it resolved for good. It's getting to be embarrassing for them.
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