What's your definition of a catastrophic engine failure? On the outside, this 5.2-liter V-10 from an Audi S6 doesn't look terrible. It sat outside without an intake manifold, but that doesn't mean the internals are junk. But they are. In fact, just about everything inside this engine is scrap metal.
That's the conclusion reached by the I Do Cars channel on YouTube. Little is known about the engine other than it came from an S6, but signs of trouble come early in this teardown. Just three minutes into the hour-long clip we see a smashed spark plug, likely caused by a wayward piston or some errant chunk of metal finding its way into the combustion chamber. And it only gets worse from there. Much worse.
The next sign of trouble comes with metal fragments found in the upper timing covers. Once the main timing cover comes off we find a loose chain and a timing gear literally snapped off. It's unclear if the gear caused the failure or was a victim of the carnage. And there's carnage. A lot of it.
That really comes to life once the heads are off. The first head reveals a piston cracked in half. Perusing the second bank of cylinders finds one piston is simply missing. Not only that, the cylinder wall looks like it was hit with 12-gauge buckshot. Once the oil pan comes off we finally see the true extent of the damage. Chunks of metal—most of which looks like the missing piston—litter the pan, but scrapes and gouges are seen everywhere inside the block. It's even cracked near the wrecked cylinder.
So what happened? Oil starvation is ruled out; the bearing surfaces looked good. Hyrdolocking is a possibility, and heavy varnish in the heads suggests the engine wasn't maintained very well. None of these are the proverbial smoking gun, though, so this mystery remains unsolved.
Not that it matters at this point. The extent of the damage means nothing of value can be salvaged from this rare Audi V-10.
Source: I Do Cars / YouTube
