This Video Of A Running Engine Cutaway Shows You Exactly What Happens When Your Motor Blows Up

Photo: Project Farm/YouTube (screengrab)

Few terms spell death for an engine quite like “seized” and “threw a rod.” Now, thanks to the magical technology known as an angle grinder, we can see what those two terms truly mean. Watch through a hole in the side of the engine as the thing seizes up and then throws a rod.

The video comes to us from YouTuber Project Farm, an apparent fan of lawnmower engine torture. (He showed us earlier what happened when he put sugar in his gas.) This time, he’s giving us an inside-look at what a catastrophic engine failure looks like:


The engine in the video had been making a terrible knocking noise, so to diagnose the fault, the Project Farm cut a giant hole into the crankcase to have a closer look. This revealed a completely toasted rod bearing allowing for tons of play between the crankshaft and connecting rod.

Instead of replacing the worn parts, the host just bolted it all back together and ran it dry. You know, because why not? After a while, the engine began slowing down before quickly seizing up. With a bit of lubricant, that engine came unseized and lived another day. Except by “day,” I mean just a few minutes, because that bad rod bearing eventually caused a connecting rod to blow into the smithereens you see in the top photo.

Seeing the innards of my blown up engine was hard enough, but watching an engine explode realtime has me doubting if I should really try driving that free Jeep Cherokee with a rod knock over 200 miles from Ohio to Detroit this weekend. Oh god.

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About the author

David Tracy

Sr. Technical Editor, Jalopnik. Always interested in hearing from auto engineers—email me. Cars: Willys CJ-2A ('48), Jeep J10 ('85), Jeep Cherokee ('79, '91, '92, '00), Jeep Grand Cherokee 5spd ('94).