Broken Prius Engine Shows Even the Best Can Fail Sometimes

Like anything Toyota-branded, these engines usually last for decades. This one didn't even make it to 100,000 miles.

Photo by: YouTube

By: Brian Silvestro

Oct 26, 2024 at 9:00am ET

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Toyota is the end-all, be-all when it comes to reliability. Few brands come close, but none can match it. Even with such a reputation, it's impossible to be perfect. This Toyota engine gave up after 73,000 miles, showing that even the best can fail sometimes.

This naturally aspirated 2ZR-FXE inline-four came out of a 2016 Toyota Prius, according to the I Do Cars YouTube channel. Seeing as how a vast majority of cars with this engine are still on the road, it's a bit unusual, especially with such low mileage.

There's no immediate damage on the outside of the engine, but things become clear once the valve cover is removed. There's a brown, milky liquid scattered about, signifying coolant and oil has mixed. That's bad news.

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Eric, the channel's host, makes his way to the head gasket, discovering signs of gasket failure around one of the cylinders, which looks suspiciously cleaner than the other three—a sign of water intrusion. Digging deeper, he finds the cylinder's rod has been bent, meaning it tried (and failed) to compress water. That'll do it.

Despite these obvious signs of damage, it's not entirely clear how this engine failed. It could've overheated, or the head gasket could've failed on its own. Eric reached out to the dealership that removed the engine from the car, but they didn't know anything about it, either. One thing is clear, though: This little four-cylinder won't be making its way back into a car any time soon.