For more than a decade, General Motors has been asking its V8 engines to do more with less. Starting around the 2014 model year, GM leaned hard into efficiency-focused tech across its small-block lineup: cylinder deactivation, complex valvetrain strategies, and ultra-thin oils like 0W-20. On paper, it all made sense. Power climbed, fuel economy improved, and the engines looked great in certification tests.
But among owners and long-term enthusiasts, confidence slowly started to crack.
That unease became impossible to ignore with the 6.2-liter L87 V8, an engine found in hundreds of thousands of GM trucks and SUVs. Between the 2021 and 2024 model years, nearly 600,000 vehicles were recalled after GM traced a wave of failures back to connecting rod issues tied to lubrication. Under real-world heat and load, the oil simply wasn’t holding up. Once the protective film broke down, metal met metal—and for some engines, the damage was sudden and catastrophic.
What really shifted the conversation wasn’t just the recall itself, but GM’s fix. For engines that passed inspection, the solution wasn’t redesigned bearings or a new oiling layout. Instead, GM told dealers to drain the thin oil and refill the engine with thicker 0W-40, along with a revised oil filter. That move landed hard with owners. For years, they’d been told these engines were designed for thin oil. Now, the manufacturer itself was quietly admitting that viscosity mattered more than expected when durability was on the line.
From that point on, the debate stopped being theoretical. GM owners began openly questioning whether chasing marginal fuel economy gains was worth the long-term risk, especially in engines that live hard lives. Full-size trucks don’t spend their days on lab test cycles—they tow, haul, idle in traffic, and run hot on long highway stretches. Those are exactly the conditions where oil film strength matters most.
Polls among GM enthusiasts tell the same story. Support for continuing with 0W-20 in future V8s is weak. Most owners say they’d rather see 0W-40, or even a return to 5W-30, the oil GM used in trucks before the efficiency push began. The priorities have changed. Owners aren’t asking for miracles—they just want confidence that their engines can survive real use, not just pass a test.
Some critics argue that thin oil was never about engine health in the first place, but about satisfying fuel economy regulations. Oils with lower viscosity can deliver small efficiency gains, and across an entire fleet, those gains matter to manufacturers. But now that regulatory pressure has eased, that trade-off looks harder to justify—especially when owners are keeping vehicles longer and expecting modern V8s to last well beyond the warranty period.
Ironically, the backlash has split in two directions. Some owners are suing GM, claiming the switch to thicker oil hurts fuel economy and resale value. Others see that same switch as overdue validation. To them, it confirms what enthusiasts have been saying for years: a high-output, hard-working V8 needs oil that can stay strong when things get hot and heavy.
Sales figures complicate the narrative. Trucks like the Chevrolet Silverado and GMC Sierra continued to sell extremely well throughout this era. Most engines never failed. But for owners who plan to keep their trucks long-term, “most of the time” isn’t good enough. The concern isn’t whether thin oil works when everything is perfect—it’s whether it leaves enough margin when conditions aren’t.
As GM prepares its next-generation small-block V8s, oil viscosity has become more than a technical detail. It’s symbolic. It represents a choice between squeezing out the last drops of efficiency or restoring trust by prioritizing durability under real-world stress.
For many GM V8 loyalists, asking for thicker oil isn’t about rejecting modern engineering. It’s about remembering a simple truth that hasn’t changed: an engine lives and dies by the strength of its oil film, and when durability matters, a little extra thickness can go a very long way.
