This Is What Happens When The Crankshaft In Your Ford EcoBoost Engine Fails

Sometimes the worst damage on a car is invisible to the naked eye. Sometimes it takes hours of disassembly to find catastrophe. That's exactly the case with this twin-turbo 3.5-liter V6 from a 2019 Ford F-150.

The I Do Cars YouTube channel got this EcoBoost mill as a core return from a sold engine. There's no info on how many miles it's traveled, but each spark plug has a red dot on the end, indicating they haven't been changed since leaving the factory. So it's likely this was a low-mileage unit when it was taken from its resting place. 

 

Eric, host of the I Do Cars channel, finds some weird stuff inside this engine. It looks like a previous mechanic used channel locks to turn the camshafts, going by the damage that's been done to them — odd considering there's a nearby space where someone could do this without harming the metal. Strangely, the timing chain rail has a 2021 date code, meaning it's a replacement part. A new timing chain isn't something you'd normally see on a low-mileage engine.

The real issue reveals itself shortly after the oil pan comes off. Eric finds the crankshaft snapped into two pieces, resting loosely in the block. The damage was enough to ruin the block and one of the pistons.

Eric suspects there isn't a single cause for this catastrophic failure, but rather a handful of smaller problems that added up. A significant amount of carbon on the pistons' ring lands could be enough to cause reduced engine compression and possibly even a misfire. Plus, damage to the camshafts and the replaced timing components show previous issues with this power plant. The combination of these problems, in addition to a flawed crankshaft, could be the reason this engine failed.

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While it isn't very common, crankshaft failures on this engine have happened before. The video below shows a similar situation with a broken crank in a 2017 F-150.

More Engine Teardowns

Mitsubishi Engine Teardown Shows What Happens When A Piston Explodes

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