Quick Facts:
- Story: Third V35A teardown from the I Do Cars YouTube channel, posted October 10, 2026.
- Engine: Toyota 3.4L twin-turbo V6, a replacement unit stamped September 20, 2025.
- Found: Warped cylinder heads, signs of a breached head gasket, and coolant in the oil.
- Not found: A spun main bearing or the large machining burrs seen in the 2026 engine.
- Cause: Overheating found. Root cause not named. Parts head to outside testing.
- Used in: Tundra, Sequoia, Lexus GX550, LX600 and LS500.
- Recalls: Three NHTSA campaigns cover 272,349 US vehicles.
 6 min read
In This Article
What the Third V35A Teardown Found
The third V35A teardown from the I Do Cars channel found overheating damage, not a spun main bearing. Toyota’s V35A is a 3.4L twin-turbo V6 used in the Tundra, Sequoia and Lexus GX550, and Toyota has recalled vehicles with it. Host Eric Berg runs a salvage business and tears down failed engines on YouTube. He posted the 52-minute video on October 10, 2026. The Drive covered it three days later.
Both heads were warped, and the head gasket showed signs of a breach. Coolant had also reached the oil. The crankshaft had not failed, so the damage stopped earlier than in the first two engines.
Nobody has named a root cause for this engine yet. Eric plans to ship the rotating assembly and an oil sample to The Motor Oil Geek for deeper testing. This article covers what he found and what the findings do not prove. It also explains what owners should do about tundra engine failure worries.
Three tools cover the first checks on a used V35A truck. A VEVOR coolant pressure tester kit finds cooling leaks, while the Block Tester BT-500 checks coolant for exhaust gas. The OBDLink MX+ scanner lists enhanced Toyota support. None of them measures head warp, which needs a straight edge and feeler gauges on a bare head.
Cooling and head gasket checks
Key Facts at a Glance
| Item | Detail |
|---|---|
| Engine stamp | September 20, 2025 |
| Truck it came from | 2023 model year, per Eric |
| Miles since install | About 12,000 to 15,000, his estimate |
| Head warp | Gaps near 0.020 and 0.016 inch |
| Main bearings | Not spun, with uneven wear |
| Next step | Outside testing of the rotating assembly |
What the V35A Teardown Found Inside the Engine
Both earlier engines had failed at the main bearings. This one turned over freely, so Eric went looking for a different problem. First, the plugs were wet at the top, which Eric blamed on rain. Turbo oil also looked watery, and the water pump was full of crust, with a visible water line.
Then the heads came off. Inner head bolts fought him, and one broke a socket, while torque was uneven from bolt to bolt. A straight edge and feeler gauges showed warped cylinder heads. Gaps measured near 0.020 inch on one head and 0.016 inch on the other. He also measured the block at about 0.0015 inch and judged it fine.
Eric called the engine overheated “clear as day.” Coolant stains marked the gaskets. He read the crusty cooling passages as a sign of combustion gas pressurizing the system. The pistons were also clean, and no rod was bent.
Bearings told a quieter story. Eric found no spun main bearings, yet the thrust bearing and some rod bearing shells showed uneven wear. For example, one groove looked like debris damage. The oil passages looked cleaner, with none of the big burrs he found in the 2026 engine.
History matters here. This is one engine with an unknown past. It arrived with partial wiring and a missing turbo, and Eric believes it sat outside. He found part of a broken fan. Assembly error, low coolant, or driving after a crash all fit the evidence. Because the history is unknown, he says he is unable to tell which.
Three V35A Teardowns Compared
| Teardown | Engine | Main finding |
|---|---|---|
| First | Original, 2022 or 2023 truck | Spun main bearings, metal in the oil |
| Second | 2026 replacement | Spun number 3 main, machining burrs |
| Third | September 2025 replacement | Overheated, warped heads, uneven bearing wear |
The first two engines destroyed their own evidence. Spun bearings spread metal everywhere, so the original trigger stays hidden. The third engine is different because the damage stopped earlier. Eric calls it a narrow window and wants to test the crank before it fails.
Uneven bearing wear also showed up in both the 2026 and 2025 replacements. Eric reads it as a point against debris being the only cause. This is his view, not a lab result.
What Toyota and NHTSA Say So Far
Toyota blames machining debris reaching the crankshaft main bearings. Three NHTSA campaigns, 24V-381, 25V-767 and 26V-320, cover 272,349 US vehicles. Our Tundra engine recall guide also lists build windows and remedies.
The 26V-320 filing says later engines use an improved main bearing, and Toyota continues to monitor the improvement. After the second teardown, Toyota sent Eric its own explanation. He then answered with a follow-up video disputing it.
What This Means for You
Do not read one teardown as a verdict on every truck. Instead, treat it as a prompt to check yours. Run your VIN at NHTSA’s recall lookup first. Then ask a Toyota dealer to read the full campaign history, including completed repairs.
A replacement engine does not guarantee a healthy truck. Eric opened two replacements, and both failed. However, the third engine’s history is partly unknown, so ask sellers for the repair order covering a swap.
Overheating is the one damage pattern here with a clear mechanism. Why this engine overheated is still unknown. Watch your temperature gauge and coolant level, especially while towing. A hot engine warps heads, so pull over early if the gauge climbs. Our cooling upgrade shootout shows how to diagnose heat in a different engine, the Jeep EcoDiesel.
Three inspection tools suit a used-truck check. The Teslong borescope has a slim probe, and its listing names spark plug holes as a fit. Also, the GoldPlug magnetic drain plug is sold for Toyota engines, so confirm the thread for your truck. A NEIKO mirror set helps you check for seepage around the gaskets and pan. No tool replaces the VIN and repair history checks above.
Gear for inspecting a used truck
Teslong 5mm Dual Lens Borescope Camera for Home/Automotive/Pipe/Car…
GoldPlug Magnetic Drain Plug fits All Toyota Nissan Lexus Infiniti …
Final Thoughts
If you own one of these trucks, read this teardown calmly. It does not solve the mystery, but it shows an overheated replacement engine with uneven bearing wear. Testing will say more. Its history is unknown, so treat it as one clue.
Do not panic, and do not wave the story away. Instead, check your VIN, keep your service records, and stop driving at the first knock or overheating. Shoppers weighing reliability across engines should also read our most reliable overlanding engines ranking.
Eric says a caller offered him two more locked-up V35A engines, and he expects follow-up videos on this one. I think owners deserve a plain explanation, and public teardowns backed by outside testing are one way to get it. Until then, a checked VIN, a tidy service file and a gauge you watch are your best protection.
Frequently Asked Questions
What did the third V35A teardown find?
Eric found warped cylinder heads, signs of a breached head gasket, coolant in the oil, and uneven bearing wear. The main bearings had not spun. He did not name a root cause.
Has Toyota named the cause of Tundra engine failure?
Toyota attributes the failures to machining debris reaching the main bearings. Eric disputes this, and outside test results are still pending.
Does a replacement Tundra engine avoid the problem?
Not by itself. Both replacement engines Eric opened failed, in different ways. The history of the third engine is unclear. Toyota says later engines use an improved main bearing.
Which vehicles use the V35A engine?
The Tundra, Sequoia, Lexus GX550, LX600 and LS500 use this 3.4L twin-turbo V6, according to the video description.
How many vehicles do the recalls cover?
Three NHTSA campaigns cover 272,349 US vehicles. Check your VIN to see whether yours is included.