--- title: "Washington reopens the GM engine question, and now it covers a million trucks" description: "US safety regulators are investigating 997,743 General Motors pickups and SUVs after 499 complaints of engine failure, many of them in vehicles that had already been through GM's recall repair. The question is no longer whether the L87 V8 has a defect. It is whether the fix worked." category: "Companies" category_url: https://boursel.com/category/companies author: "Sofia Marchetti" published: 2026-08-21T11:07:00.000Z updated: 2026-08-21T11:07:00.000Z canonical: https://boursel.com/article/washington-reopens-the-gm-engine-question-and-now-it-covers-a-million-trucks tags: ["general-motors", "nhtsa", "recalls", "automotive", "product-safety"] --- # Washington reopens the GM engine question, and now it covers a million trucks US safety regulators are investigating 997,743 General Motors pickups and SUVs after 499 complaints of engine failure, many of them in vehicles that had already been through GM's recall repair. The question is no longer whether the L87 V8 has a defect. It is whether the fix worked. The National Highway Traffic Safety Administration is examining [997,743 General Motors trucks and SUVs after 499 complaints of engine failure](https://www.investing.com/news/stock-market-news/us-regulator-probes-nearly-1-million-gm-vehicles-for-engine-failure-93CH-4871248), the agency said on Friday. The vehicles are Cadillac Escalades, Chevrolet Silverado 1500s and GMC Yukons from the 2021 to 2026 model years, fitted with GM's 6.2-litre L87 V8. What makes this different from the earlier rounds is the population being examined. The complaints include engines that failed in vehicles that had already received GM's recall remedy, and the agency says it will assess how effective that remedy has been. ## What an NHTSA investigation is The agency's Office of Defects Investigation works in stages. A preliminary evaluation establishes whether there is a pattern worth pursuing. An engineering analysis, the next step up, examines how widespread a defect is and whether it presents an unreasonable safety risk. A recall query is narrower: it asks whether a recall that has already happened did what it was supposed to. None of these compels anything by itself. What they can produce is a finding that pushes a manufacturer into a recall, or an expansion of one, and manufacturers usually act before the agency reaches a formal determination. The cost falls on the maker: inspection, repair or replacement, at no charge to the owner. ## How the case got here The sequence matters, because the numbers in circulation come from different stages of it. In January 2025 the agency opened a preliminary evaluation covering [about 877,000 vehicles on 39 complaints](https://www.wardsauto.com/news/archive-auto-nhtsa-odi-open-safety-probe-877k-gm-vehicles-over-engine-failures-62l-v8/737966/). The failure mode described then is the one still at issue: a connecting rod bearing fails, and the engine either seizes or the rod breaches the block. Owners reported no warning before it happened, which is what makes it a safety matter rather than a durability one. An engine that stops without notice at highway speed takes the power steering and the power brake assist with it. In April 2025 GM recalled [close to 600,000 vehicles](https://www.cbsnews.com/news/gm-recall-escalade-silverado-suburban-sierra-engine-failure-risk/). The remedy was an inspection, replacement of the engine where damage was found, and for the rest a switch to a higher-viscosity oil with a revised filter and oil cap. GM attributed the underlying problem to manufacturing at a supplier, saying crankshafts and connecting rods had been produced out of specification. The agency later upgraded its work to an engineering analysis after receiving more than 1,100 reports of bearing failures, and looked at whether earlier model years were affected. Friday's action, on 499 complaints across nearly a million vehicles including 2025 and 2026 model years, is the largest population yet. ## The awkward part for GM An oil change is a cheap remedy. Replacing an engine is not, and the difference between the two is roughly the difference between a manageable warranty charge and a material one. That is the commercial question inside the safety one. If the agency concludes the higher-viscosity oil does not prevent the failure in engines that were built with out-of-specification parts, the remedy for a large share of a million vehicles becomes mechanical rather than chemical. GM has not disclosed a reserve for that outcome, and the investigation is at too early a stage to assume it. GM has said it will cooperate with the agency, which is the standard response and does not indicate what it expects to find. ## What owners should know An open investigation is not a recall, and there is nothing an owner is required to do. Complaints can be filed with NHTSA directly, and owners can check whether a specific vehicle has an open recall using its vehicle identification number on the agency's site. If a recall follows, notification comes by mail and the repair is free. ## Sources - [US regulator probes nearly 1 million GM vehicles for engine failure](https://www.investing.com/news/stock-market-news/us-regulator-probes-nearly-1-million-gm-vehicles-for-engine-failure-93CH-4871248) - [US auto safety regulators open investigation into GM engine failures, including popular Silverados](https://www.yahoo.com/news/us-auto-safety-regulators-open-164130894.html) - [NHTSA opens probe of over 877K GM vehicles for engine failures](https://www.wardsauto.com/news/archive-auto-nhtsa-odi-open-safety-probe-877k-gm-vehicles-over-engine-failures-62l-v8/737966/) - [GM recalls nearly 600,000 trucks and SUVs over risk of engine failure](https://www.cbsnews.com/news/gm-recall-escalade-silverado-suburban-sierra-engine-failure-risk/)