NHTSA Opens Probe Into Nearly 1 Million GM Trucks and SUVs Over Engine Failures

The National Highway Traffic Safety Administration has opened a broader engineering analysis into engine failures involving nearly 1 million General Motors trucks and sport utility vehicles equipped with the company’s 6.2-liter L87 V8. Reuters reported Friday, citing the regulator, that the review covers 997,743 vehicles from the 2021 through 2026 model years after NHTSA received 499 complaints alleging engine failures following recall repairs.

The investigation reaches some of GM’s core full-size vehicle lines, including L87-equipped versions of the Chevrolet Silverado 1500, Tahoe and Suburban, GMC Sierra 1500, Yukon and Yukon XL, and Cadillac Escalade and Escalade ESV. The agency’s move does not itself recall all 997,743 vehicles. An engineering analysis is a deeper defect investigation intended to determine the scope and safety consequences of a suspected problem and whether earlier corrective action was adequate.

That distinction is important because GM already recalled hundreds of thousands of L87-powered vehicles in 2025. The new review puts the earlier remedy under scrutiny while also examining failures reported in engines built outside the production window that GM had identified as potentially defective.

The new analysis extends a recall that covered 597,571 vehicles

GM’s 2025 recall covered 597,571 vehicles equipped with the L87 engine and built during a suspect period running from March 1, 2021, through May 31, 2024. NHTSA’s recall report identified 2021 through 2024 versions of the Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban and Tahoe, and GMC Sierra 1500, Yukon and Yukon XL.

The defect involved manufacturing problems affecting connecting rods and crankshafts. According to the official recall filing, sediment on connecting rods or in crankshaft oil galleries could damage rod bearings, while some crankshafts were produced with dimensions or surface finishes outside specification. Either condition could lead to engine damage or failure. NHTSA said an engine failure during operation could cause a loss of propulsion and increase the risk of a crash.

GM’s field review before the recall was substantial. The automaker identified 28,102 potentially related field complaints or incidents involving the suspect population, including 14,332 allegations of loss of propulsion. Its recall chronology also listed 12 potentially related alleged crashes, 12 potentially related alleged injuries, and 42 potentially related fire allegations, although the filing said causation was unclear in most of the fire reports.

The original recall did not end the regulator’s work. In October 2025, NHTSA opened a separate engineering analysis covering an estimated 286,051 vehicles outside the recall population after receiving 1,157 reports of engine bearing failures, including 173 involving vehicles that were not covered by recall 25V-274. Agency documents said the review was intended to examine the scope and severity of failures beyond the manufacturing period GM had selected.

NHTSA is testing whether the recall remedy is holding up

The focus shifted again after owners reported failures in vehicles that had already been repaired. NHTSA opened a Recall Query in January 2026 after receiving 36 complaints alleging engine failures following completion of the recall remedy. The agency said those complaints included failures after both forms of corrective action offered by GM.

Under the 2025 remedy, dealers were instructed to inspect affected engines. Engines that did not pass inspection could be repaired or replaced. Vehicles that passed inspection received higher-viscosity engine oil, a new oil fill cap, a replacement oil filter and an owner-manual insert. GM also told NHTSA that repaired or replacement components would fall outside the suspect supplier production window and that manufacturing improvements had been implemented by June 1, 2024.

The January query therefore raised a narrower but consequential issue: whether the remedy itself was sufficient. NHTSA’s opening document said owners had alleged failures in vehicles that received the oil-related remedy as well as in vehicles that received replacement engines. The latest complaint count reported by Reuters, 499 post-remedy failures, is far above the 36 complaints cited when the Recall Query began seven months ago.

Separate automotive reports reviewing the new opening materials also indicate that NHTSA is looking at L87-equipped vehicles from later model years, including 2025 and 2026 vehicles that were not part of the original 2025 recall. That wider model-year range does not mean every L87 engine from those years is defective. It means the agency is assessing whether the earlier manufacturing cutoff and repair strategy accurately captured the safety risk.

For GM, the issue is no longer limited to identifying a historical batch of components. Investigators now have to distinguish among several possibilities, including failures tied to the original supplier defects, failures that may have survived the inspection process, problems involving replacement engines, and failures in later production that may have a different cause. The investigation can narrow the population again if the evidence supports that outcome, or it can lead to a wider safety action if NHTSA finds the existing recall scope or remedy inadequate.

A broader recall is possible, but not automatic

NHTSA’s escalation to an engineering analysis is a formal step in its defect-investigation process, not a determination that all vehicles under review need another repair. The agency says its investigators use consumer complaints, warranty information, crash and injury data, parts information, testing and manufacturer records to determine whether a safety-related defect exists and how broadly it extends.

If NHTSA concludes that the existing remedy does not address the risk, GM could be required to revise the repair program, expand the affected population or take other corrective action. If the evidence shows that failures outside the original recall are unrelated or do not reflect a broader safety defect, the agency could close or narrow the investigation. The current review is designed to resolve those questions rather than assume an outcome.

Owners of affected GM vehicles can use NHTSA’s VIN-based recall lookup to determine whether an unrepaired safety recall applies to a specific vehicle. The current engineering analysis by itself does not create a new recall repair obligation for every vehicle in the 997,743-unit population, so the status of an individual truck or SUV still depends on its VIN and any existing campaign that applies to it. The next concrete development will come from NHTSA’s engineering analysis and GM’s responses to the agency’s information requests, which will determine whether the regulator keeps the existing recall boundaries, requires a different remedy, or expands the safety action to additional L87-equipped trucks and SUVs.