NHTSA Probe Targets Over 870,000 GM Trucks and SUVs

General Motors began 2025 facing a major issue: the National Highway Traffic Safety Administration (NHTSA) launched a formal investigation into the company’s widely used 6.2-liter L87 V8 engine. The probe affects 877,710 full-size trucks and SUVs, after multiple reports of engine failures were filed with the agency. The investigation has since led to a large-scale recall and a stop-sale order.

In some cases, these engine failures occurred while driving down the highway or just a few miles into vehicle use. Needless to say, they pose serious safety risks.

Which Vehicles Are Affected by the L87 Engine Recall?

The list of affected vehicles includes the not-rookies-to-recall Chevrolet Silverado 1500, Tahoe, and Suburban; the Cadillac Escalade and Escalade ESV; and the GMC Yukon, Yukon XL, and Sierra 1500, model years 2021 to 2024, all powered by the small-block V8 engine. The American automaker hasn’t pinpointed the exact issue with the problematic power plant, only saying that the connecting rod and/or crankshaft components have unspecified manufacturing defects.

Inside the Failure: Teardown Reveals Severe Engine Damage

But what happens inside the L87 V8 engine when it fails? Internet mechanic I Do Cars got its hands on one for an engine teardown, providing a more intimate look at the internals of one of GM’s V8 mill that faced a catastrophic failure. The engine in question is said to have been recalled (from a 2022 GMC Yukon Denali), although details of how he got it weren’t disclosed.

The teardown starts optimistically: the engine can be cranked by hand, indicating no fully seized components. However, the first sign of trouble appears on the pushrods, which exhibit abnormal wear. The lifters, though none have completely collapsed, show signs of debris exposure, with one in particularly poor condition.

Connecting Rod, Crankshaft Issues Confirmed by Damage

Removing the oil pan reveals more – a lot more. The internal oil has turned carbon-black, indicating severe overheating and oil breakdown. All eight connecting rods are completely shot, showing extensive damage. The camshaft lobe is also missing a chunk, while the block’s front shows scoring, suggesting the crankshaft struck the block.

The teardown reveals significant and unusual damage for a relatively young and modern engine, though it aligns with GM’s claim that the problem lies with the connecting rods and crankshafts. It’s also likely that this engine failed gradually, unlike other reported cases of instant engine failure. As the presenter notes, the owner likely ignored early signs of engine trouble, leading to more catastrophic damage.

GM Issues Recall Fix, But Owners Are Pushing Back

As part of the recall, GM has already provided a solution to the issue. Affected engines that haven’t failed yet will have their oil replaced with thicker 0W-40 oil (replacing the former 0W-20), offering increased protection at operating temperatures. They will also get a new oil filter and oil fill cap that reflects the change. Engines that were shot will be replaced.

However, not everyone’s happy with GM’s band-aid solution to this widespread problem. A lawsuit claims that replacing the engine’s oil with higher viscosity would decrease fuel economy. The lawsuit claims that “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.”

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