GM Truck Owners With ‘Fixed’ 6.2L V8s Sue Over Reduced Fuel Economy
Owners with repaired or replaced 6.2-liter GM V8s say their fuel economy could tank after the fix. Now, they're suing. The post GM Truck Owners With ‘Fixed’ 6.2L V8s Sue Over Reduced Fuel Economy appeared first on The Drive.
General Motors really can’t catch a break this year. As if the ongoing V8 fiasco itself wasn’t enough of a bugbear, the company is now being sued for it. Given the scope of the recall campaign—the company has more than 600,000 trucks to inspect and/or repair—it’s not surprising that a group of owners has banded together to pursue legal action. But what is surprising is why; these owners aren’t suing because their trucks were sidelined (for months, in some cases) or because the quality of the repair was poor. Instead, they’re suing because GM’s solution to the problem allegedly results in worse gas mileage.
The purported culprit is GM’s updated oil viscosity requirement. Originally, the maintenance schedule for the L87 6.2-liter V8 required 0W-20. GM’s updated guidance requires the use of 0W-40. A higher number (or “weight”) refers to the oil’s viscosity—or how thick it is. Higher viscosity oils cling to component surfaces more effectively than lower viscosity oils. This makes them better at their primary job (lubricating engine components), at the expense of increased drag.
Imagine trying to swim laps in a pool filled with vegetable oil rather than water. Setting buoyancy aside for the moment, you’d need a lot more energy to get from one end to the other in the oil, no matter how “slippery” it might make you. This is exactly what could be happening to the L87’s internal components, only trucks don’t run on carbs; they run on gasoline.* These owners are worried that they’re going to need quite a bit more of it, translating to higher long-term ownership costs.
“Thicker oil may (or may not) help mitigate the engine defect, but it will also materially decrease fuel economy and require owners to purchase hundreds of extra gallons of gasoline over their vehicles’ lifespans,” the suit says. “Thus, as the result of the underlying defect and GM’s recall remedy, owners are presented with two bad options: do nothing and risk catastrophic engine failure or get the recall and pay hundreds of dollars more for gasoline.”
Based on the 2025 Chevy Suburban owner’s manual available on Chevy’s website, the higher-viscosity oil requirement was not carried over to the updated L87 sold in trucks built after the recall window. The maintenance instructions (above) still specify 0W-20.
The suit (McNamara et al. v. General Motors LLC) was filed on behalf of seven owners in Pennsylvania, according to Law360.com (registration required), but they’re hoping to recruit owners nationwide to shore up their numbers.
A GM spokesperson told The Drive that the company is reviewing the complaint but has no further comment.
*Complex hydrocarbons are technically carbohydrates with extra steps, but please do not drink the delicious hydrocarbons. And don’t try to swim in vegetable oil.
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The post GM Truck Owners With ‘Fixed’ 6.2L V8s Sue Over Reduced Fuel Economy appeared first on The Drive.
