Sometimes it can be tough to diagnose an engine problem. And sometimes, you get not one, not two, or even three big holes to show you the problem. This Nissan VQ engine pulled from a 2017 Infiniti Q50 Hybrid has four unplanned "inspection ports" following a catastrophic failure that must have been epic to experience in real-time.
Look closely at the photo atop this article, specifically the big hole in the block. That's actually two holes you're looking through, and a third with a broken rod sticking out at the top of the photo. once the camera pans underneath, we see hole number four chiseled out of the oil pan. This 3.5-liter V-6 clearly went out with one hell of a bang.
Mind you, this is just damage visible before the teardown begins. As with other videos from the I Do Cars YouTube channel, we start at the top half of the engine. And it doesn't look that bad. Occasional bits of metal are found, but the heads are pretty clean, and there isn't a crazy amount of wear on the camshafts. But as the parts come off, things get worse. Gobs of metal bits are caked in and around the cam gears, and the cam lobes do show more wear once they're out and inspected. Getting the timing cover off requires dropping the oil pan, and as you can guess, it's filled with mangled metal nuggets.
Here's where the teardown gets interesting. With the heads off it becomes clear that, at some point, someone with questionable skill was wrenching on the engine. Scour marks on the deck appear to be from a grinding tool, possibly used to clean the surface before reinstalling a head gasket. There's also a coolant tube that was reinstalled with prolific silicone instead of gaskets. Could this have contributed to the failure? It's impossible to say, but the sketchy repairs likely didn't help matters any.
Of course, the headlining act of this VQ35 tour is the bottom end, and destroyed doesn't even come close to describing it. One piston is basically a pancake. Two other pistons are severely damaged, and the others show considerable wear. The block is chewed to bits, the crankshaft is torn up, and rods are either bent or broken. It's the gnarliest engine we've seen in a long time.
What caused the damage? The specific event is unknown, but evidence suggests prolonged driving with inadequate oil ultimately killed this engine. And it likely wasn't a surprise event either. A bearing could've spun, possibly related to ill-fitting head gaskets leaking coolant into the oil. As the engine continued on, metal from the spun bearing circulated through the engine, causing more wear on vital components leading to what we have here. Going by the evidence, it's the most plausible explanation.
The moral of the story here is to check your oil and change it regularly. It's far, far cheaper than rebuilding or replacing an engine.
