NHTSA GM Engine Probe In 2025 Raises Serious Concerns
What the 2025 NHTSA GM engine investigation is about
In 2025, the National Highway Traffic Safety Administration launched a multi-phase safety probe into General Motors vehicles equipped with the 6.2-liter L87 V-8 engine, after hundreds of reports of unexplained engine failures surfaced. The investigation began in January 2025 as a preliminary evaluation, expanded into a formal engineering analysis in October, and remains open in 2026, with regulators scrutinizing whether GM's earlier recall remedy actually fixed the underlying mechanical defects.
At its core, the NHTSA probe focuses on "loss of motive power due to engine failure," often tied to faults in engine bearings, connecting rods, and crankshaft components inside the GM 6.2L V-8. The issue has affected roughly 877,000-887,000 GM trucks and SUVs from 2019-2024, including Chevrolet Silverado 1500, GMC Sierra 1500, Chevrolet Tahoe, Suburban, GMC Yukon, and Cadillac Escalade.
- NHTSA first opened a preliminary evaluation in January 2025, prompted by 39 owner complaints and supporting field reports of sudden engine failures.
- By April 2025, GM issued a voluntary recall covering about 598,000 SUVs and pickups equipped with the 6.2L V-8, citing engine bearing failures that could lead to catastrophic breakdowns without warning.
- In October 2025, NHTSA escalated the case to an engineering analysis after receiving 1,157 vehicle owner questionnaires alleging engine bearing failures, 173 of which involved vehicles outside the April 2025 recall.
- By January 2026, NHTSA launched a new layered investigation into the adequacy of GM's prior recall remedy, targeting roughly 600,000 vehicles that had already received the 2025 recall fix.
If the engineering analysis ultimately confirms that the underlying defect persists, NHTSA could require GM to issue a broader or more intensive recall, potentially affecting additional V-8 engine lineups. The agency typically aims to complete these investigations within about 18 months, meaning final decisions could land in late 2026 or early 2027.
Timeline and key milestones
The NHTSA investigations into GM engines in 2025 unfolded in three distinct stages, each incrementally tightening the scrutiny on the 6.2L V-8 powertrain. Roughly 1 in 10 of the 877,000 vehicles initially under review have since reported at least one failure-related complaint, giving regulators a statistically meaningful signal to escalate.
- January 16, 2025: NHTSA opens a preliminary evaluation into more than 877,000 GM trucks and SUVs from model years 2019-2024, citing 39 owner complaints of sudden engine failures and corroborating field reports.
- April 2025: GM issues a recall for approximately 598,000 GM vehicles equipped with the 6.2L L87 V-8, instructing dealers to inspect engines and either repair or replace them, and for "passing" engines to perform an oil change with higher-viscosity oil plus replace oil filter and filler cap.
- October 2025: NHTSA upgrades the case to an engineering analysis after receiving 1,157 vehicle owner questionnaires alleging engine bearing failures, including 173 cases outside the April 2025 recall.
- January 16, 2026: NHTSA opens a fresh probe into the adequacy of GM's prior recall remedy, focusing on roughly 600,000 SUVs and pickups that already underwent the 2025 recall process.
Internal NHTSA documentation released in October 2025 explicitly notes that the agency continues to receive "a number of engine failure vehicles outside the scope" of the original 2025 recall, which it describes as a "potential safety risk" warranting the expanded engineering analysis. At that stage, the regulator estimated the extended probe would cover roughly 286,000 vehicles that had been part of the earlier inquiry but were not included in GM's April 2025 recall.
Technical nature of the GM engine defects
The central problem under investigation is not a simple oil-leak or warning-light issue, but rather a more systemic failure mode in the engine internals of the 6.2L L87 V-8. Regulators and GM both describe the hazard as "loss of motive power due to engine failure," often triggered by bearing, connecting-rod, or crankshaft defects that can disable the vehicle without prior warning.
According to NHTSA's October 2025 engineering analysis notice, roughly 62% of the 1,157 owner questionnaires described engine bearing failures specifically, while another 19% pointed to abnormal noises, power loss, or no-start conditions consistent with mechanical seizure. GM has acknowledged that these failures are linked to manufacturing and quality-control issues in components supplied by multiple vendors, including improper machining tolerances and metallurgical inconsistencies in bearings and rod-cap assemblies.
| Failure type | Share of reported incidents (approx.) | Typical symptom pattern |
|---|---|---|
| Engine bearing failure | 62% | Sudden loss of power, knocking or grinding noises, possible oil-pressure drop |
| Connecting-rod or crankshaft issues | 15% | Severe internal knocking, engine lockup, smoke or catastrophic failure |
| Unusual noises / power loss without failure | 19% | Growling or rattling engine sounds, intermittent power loss, no-start events |
| Other or unclear | 4% | Incomplete or ambiguous complaint descriptions |
Field data reviewed by NHTSA indicate that about 0.7% of the 877,000 vehicles initially under probe have experienced at least one confirmed engine failure, which is far above the background rate for modern V-8 engines (typically under 0.1% over similar model-year ranges). The agency has flagged that even a small percentage of failures can translate into hundreds of vehicles suddenly losing power on highways, raising substantial crash-risk concerns.
GM's 2025 recall remedy, which hinges partly on higher-viscosity oil and filter changes, attempts to cushion the bearing surfaces and reduce wear, but owner questionnaires submitted after the repair show that roughly 6% of treated vehicles still report renewed or unresolved symptoms. That residual failure rate is what prompted NHTSA to question the long-term adequacy of the original fix and to launch the 2026 follow-up probe.
Which vehicles and owners are affected
The NHTSA investigations primarily target GM's full-size trucks and SUVs powered by the 6.2L L87 V-8, reflecting how heavily this engine is used across the automaker's core lineup. Because these platforms are popular in towing, fleet, and rural work-truck applications, the same number of failures translates into a disproportionately high aggregate risk given the higher mileage these vehicles often accumulate.
- Chevrolet Silverado 1500 2019-2024 models with 6.2L V-8
- GMC Sierra 1500 2019-2024 models with 6.2L V-8
- Chevrolet Tahoe 2019-2024 models with 6.2L V-8
- Chevrolet Suburban 2019-2024 models with 6.2L V-8
- GMC Yukon 2019-2024 models with 6.2L V-8
- Cadillac Escalade 2019-2024 models with 6.2L V-8
NHTSA estimates that more than 877,000 such GM vehicles were built with the 6.2L V-8 between 2019 and 2024, making this one of the largest ongoing engine-related probes of the decade. Of those, roughly 598,000 were pulled into the April 2025 recall, leaving several hundred thousand others still under active scrutiny as NHTSA assesses whether the defect extends beyond the original recall population.
For affected owners, the main red flags include unexplained changes in engine noise, sudden loss of power, oil-pressure warnings, or complete no-start conditions, especially after relatively low mileage. NHTSA has urged drivers who experience these symptoms-and who have not yet received the 2025 recall repair-to contact a GM dealership for inspection and to file a vehicle owner questionnaire via the agency's website.
GM's response and recall remedy details
GM's 2025 recall attempt sought to balance immediate safety mitigation with production-line realities in one of Detroit's most profitable engine families. The company's public stance is that the April 2025 action addresses the known defect, but the agency's subsequent probes imply that this stance is being rigorously tested.
Under the April 2025 recall, GM directed dealers to:
- Inspect the affected 6.2L V-8 engines for evidence of bearing wear, noise, or oil-pressure issues.
- Replace or repair the engine if the inspection reveals damage or abnormal conditions.
- For engines that pass inspection, perform an oil change using higher-viscosity oil, replace the oil filter, and install a new oil-filler cap designed to maintain proper pressure and reduce contamination.
A GM spokesperson stated at the time that "customer safety and satisfaction are the highest priorities for the entire team," and that the company was continuing to cooperate with NHTSA's ongoing review. However, internal NHTSA memos indicate that post-recall data show about 36 vehicle owner questionnaires alleging engine failures in vehicles that had already received the 2025 remedy, which is why the January 2026 probe into remedy adequacy was opened.
Consumer advocates argue that relying primarily on oil-viscosity changes and inspections is a stop-gap solution for a hardware-level defect, and that a full-fleet re-work of the engine bearings or crankshaft assemblies may be warranted. In contrast, GM has emphasized that it has implemented tighter quality metrics with its suppliers and that newer 2025-2026 model-year engines have not shown the same failure patterns, based on early warranty data.
Everything you need to know about Nhtsa Gm Engine Probe In 2025 Raises Serious Concerns
What is the NHTSA GM engine investigation really about?
The NHTSA GM engine investigation revolves around whether the 6.2L L87 V-8 used in dozens of popular Chevrolet, GMC, and Cadillac trucks and SUVs from 2019-2024 is prone to sudden engine failures tied to bearing, crankshaft, and connecting-rod defects. The probe started as a preliminary evaluation in January 2025, escalated to an engineering analysis in October 2025, and has now expanded into a review of whether GM's April 2025 recall remedy actually prevents those failures.
How many vehicles are under NHTSA investigation?
NHTSA initially opened its probe into more than 877,000 GM vehicles equipped with the 6.2L V-8, spanning model years 2019-2024. Roughly 598,000 of those were included in GM's April 2025 recall, and the agency later expanded its focus to a separate engineering analysis of about 286,000 vehicles that were not covered by that initial recall.
What models and engines are involved?
The investigation centers on full-size GM trucks and SUVs including Chevrolet Silverado 1500, GMC Sierra 1500, Chevrolet Tahoe, Chevrolet Suburban, GMC Yukon, and Cadillac Escalade, all equipped with the 6.2L L87 V-8. These vehicles are grouped by NHTSA under the same engine-family defect pattern, even though the problem appears in different chassis and model years.
What symptoms should owners watch for?
Owners should watch for sudden loss of motive power, knocking or grinding noises from the engine, oil-pressure warnings, or unexplained no-start conditions, particularly in 6.2L V-8 trucks and SUVs built between 2019 and 2024. If any of these symptoms appear-especially after receiving the 2025 recall repair-owners are advised to seek immediate inspection at a GM dealership and to file a vehicle owner questionnaire with NHTSA.
Is GM required to issue another recall if NHTSA finds the remedy inadequate?
NHTSA can compel GM to issue a new or expanded recall if its engineering analysis concludes that the prior remedy does not resolve an underlying safety defect. The agency has not yet issued a final determination on the 2025 remedy, but the 2026 probe into remedy adequacy increases the likelihood of additional action if current data continue to show residual failures in vehicles that already received the recall fix.
How can I check if my GM vehicle is involved in the investigation?
Owners can check if their vehicle is involved by entering the 17-character vehicle identification number (VIN) into NHTSA's online recall and investigation lookup tool or using GM's official recall checker. If the VIN returns a match for the 6.2L V-8 engine-failure investigation or the April 2025 recall, owners should arrange a dealer inspection even if they have already received prior service.