General Motors (GM) is facing renewed scrutiny over its L87 V8 engine after a 2025 safety recall affected nearly 600,000 full-size trucks and SUVs. The recall, prompted by potential manufacturing defects in connecting rods and crankshafts, led dealers to switch from 0W-20 to thicker 0W-40 oil.

However, owners report persistent engine problems even after replacements, sparking widespread criticism and a demand for thicker oil formulations in future V8 engines. This dissatisfaction has escalated into a formal U.S. National Highway Traffic Safety Administration (NHTSA) remedy investigation launched in January 2026.