The Nissan VQ engine pulled from a 2017 Infiniti Q50 Hybrid underwent a catastrophic failure, resulting in four large holes in the block. Upon initial inspection, the damage appeared to be limited to the top half of the engine, with occasional metal bits but relatively clean heads. However, as the teardown progressed, more severe damage was revealed. The cam gears were caked with metal, and the cam lobes showed significant wear. The timing cover removal required dropping the oil pan, which was filled with metal fragments.
Upon further inspection with the heads removed, evidence of questionable repairs became apparent. Scour marks on the deck suggested the use of a grinding tool, possibly to clean the surface before reinstalling a head gasket. Additionally, a coolant tube was reinstalled with excessive silicone instead of gaskets, potentially contributing to the engine failure.
The most severe damage was found in the bottom end of the engine. One piston was completely flattened, two others were severely damaged, and the rest showed considerable wear. The block, crankshaft, and rods were all extensively damaged. The specific cause of the failure remains unknown, but evidence suggests prolonged driving with inadequate oil may have been a contributing factor. A spun bearing, possibly related to leaking head gaskets, could have initiated the damage, with metal circulating through the engine and causing further wear on vital components.
Ultimately, the lesson learned from this catastrophic engine failure is the importance of regularly checking and changing the oil. Neglecting this basic maintenance task can lead to costly repairs or engine replacements. Proper maintenance can help prevent catastrophic failures like the one experienced by this Nissan VQ engine.