Toyota’s multiple recalls for its new twin-turbo V6 in the Tundra and some of its SUVs must be frustrating, but at least the company has solved the problem. Owners get a new engine, and while that’s bad for them and the balance sheet, that’s as far as it goes. Right? Not so fast. A new teardown of one of those blown V6 engines has the experienced engine tearer-downer calling out Toyota’s explanation of the failures.
- Base Trim Engine
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3.4L Twin-Turbo V6 ICE
- Base Trim Transmission
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10-speed automatic
- Base Trim Drivetrain
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Four-Wheel Drive
- Base Trim Horsepower
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358 HP @5200 RPM
- Base Trim Torque
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406 lb.-ft. @ 2000 RPM
- Base Trim Fuel Economy (city/highway/combined)
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17/23/19 MPG
- Base Trim Battery Type
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Lead acid battery
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Debris Gets The Blame, But Is It The Cause?
Officially, the problem that has led to recalls of the V35A engine in more than 200,000 vehicles is manufacturing debris. Specifically, it’s debris left inside the oil passages that gets flushed downstream and wreaks havoc on sensitive parts like the engine’s rod bearings.
Eric Berg of I Do Cars fame says he has been trying to get one of these engines since the issues first surfaced. But since the failed engines are being replaced under warranty or recall, it’s nearly impossible to get one. Toyota wants the cores back, and it is getting them. Finally, he found one.
We’ve posted Berg’s teardowns before. It’s fascinating looking through blown-up engines as he tries to find the root cause or at least show us the carnage.
After the valve covers come off, we’re already seeing signs of damage to the engine. There are some marks on the cam lobes on one bank at just 38,000 miles. There’s also some buildup of oil with metal debris in the corner of the head.
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The first sign of a real problem, though, is an idler gear in the timing chain system. The gear is tough to turn by hand, and once it’s out the bearing is full of large pieces of debris.
Silvery Sparkles Everywhere
An oil pan full of silvery sparkles is exactly what we had expected since the engine would barely turn over. When the engine’s bed plate comes off, the real damage is visible. Two of the four main bearings are spun, where the bearing surface rotates out of place in its housing. It’s exactly what you’d expect from manufacturing debris ending up in the oil. The pieces of material get caught in the bearing and cause big problems for the rotating parts.
When the pistons come out, Berg says that now we have things to talk about. The connecting rod bearings are significantly worn, through multiple layers of material. The connecting rods also have wear damage on their faces at the crankshaft end.
Back to the main bearings. “The recall claimed that there was debris left in the oil channels of the engine,” Berg says. “This kind of debris isn’t that kind of debris,” he adds.
After he goes through the entire engine, Berg says that he doesn’t believe that debris was the failure. Actually, he calls it “total BS.” His reasoning? That the rod bearings on the crankshaft had no visible damage or wear. “How does it know to target just the main bearings and not the rod bearings?” he asks, as they share oil channels. He also points out there was no manufacturing debris or damage to the camshafts, caps, or towers.
“There is something wrong with these engines,” he said. Despite that, “I don’t hate this engine,” he said, calling it “easy to work on” and adding “there are good things about it.”
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We’ve reached out to Toyota to ask about the video and if the company has more to add regarding the damage shown in this video. We’ll update the post if more information becomes available.
Source: I Do Cars / YouTube
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