Owners of 2014 through 2024 Chevrolet Silverado and GMC Sierra trucks equipped with GM’s L87 6.2-liter V8 are facing costly engine repairs as mechanics across the country flag a pattern of lifter failures. The National Highway Traffic Safety Administration has opened a preliminary evaluation into sudden engine failures in vehicles with the L87 powerplant, and GM has separately recalled nearly 600,000 trucks over connecting-rod and crankshaft defects tied to supplier manufacturing problems. Together, these actions raise a pointed question: whether two seemingly distinct failure modes share a common root in the same manufacturing era.
Why lifter and engine failures in L87-equipped trucks demand attention now
The stakes for truck owners are immediate and financial. Independent shops report repair bills exceeding $4,000 for lifter replacements in the Active Fuel Management system, a technology GM uses to deactivate cylinders for fuel savings. When lifters collapse or their guide trays fail, the engine can lose power without warning, sometimes while traveling at highway speed. That risk prompted NHTSA to open its preliminary evaluation into sudden L87 failures affecting Silverado and other models in the lineup.
Separately, GM filed recall 25V-274 covering nearly 600,000 vehicles after federal documents linked connecting-rod and crankshaft component problems to supplier manufacturing and quality issues. Those defects can cause engine failure while driving, according to the recall filing. The recall and the NHTSA evaluation target overlapping model years and the same engine family, which raises the possibility that the problems are connected rather than isolated.
One working hypothesis circulating among technicians is that upstream oil-pressure fluctuations caused by defective connecting-rod components could accelerate wear on the AFM lifter guides. If a rod bearing is slightly out of specification, it can alter oil flow and pressure at the lifter galley, starving the hydraulic lifters of the consistent lubrication they need to cycle between active and deactivated states. Under that theory, the lifter failures and the connecting-rod defects would represent a single manufacturing-era vulnerability rather than two coincidental problems. No official engineering analysis from GM has confirmed or denied this link, and the hypothesis remains untested in any published study.
Federal actions and supplier defects behind the L87 engine problems
The federal record provides two concrete data points. First, NHTSA opened a preliminary evaluation focused on sudden failures in vehicles equipped with the L87 V8. The agency’s evaluation covers the Silverado and other GM trucks and SUVs sharing that engine. Second, GM issued recall 25V-274 for nearly 600,000 vehicles after identifying connecting-rod and crankshaft component problems. The automaker attributed those defects to supplier manufacturing and quality issues, though GM has not publicly named the supplier involved.
The recall documents state that engine failures can occur while driving due to these component problems. That language is significant because it establishes a safety risk beyond routine maintenance. A truck that stalls on a freeway or loses power while towing creates hazards not just for its driver but for surrounding traffic. The recall covers a broad production window, which suggests the supplier issue persisted across multiple model years rather than appearing in a single batch.
Mechanics who work on these trucks daily describe a pattern that predates the recall. Lifter tick, a distinctive tapping noise at startup or under load, has been a known complaint in GM’s AFM-equipped V8 engines for years. What changed recently is the frequency and severity. Shops report seeing collapsed lifters in trucks with fewer miles than earlier failure patterns suggested, and the damage often extends to the camshaft lobes, turning a $4,000 repair into a near-complete top-end rebuild.
The AFM system itself has drawn criticism from owners and technicians since its introduction. It relies on oil pressure to lock and unlock lifters as the engine management computer switches between eight-cylinder and four-cylinder operation. Any disruption to oil delivery, whether from a clogged screen, a worn pump, or a bearing defect elsewhere in the rotating assembly, can leave a lifter in the wrong position. That mechanical reality is what gives the connecting-rod hypothesis its plausibility, even without formal confirmation.
Gaps in the evidence and what truck owners should watch
Several pieces of the puzzle are still missing. No public warranty-claim data from GM dealers has surfaced showing failure rates broken down by model year or build date. Without that data, it is difficult to determine whether certain production runs carry higher risk than others. The NHTSA complaint database contains individual owner reports, but no published analysis has sorted lifter-specific complaints from connecting-rod failures in a way that would confirm or rule out a shared cause.
GM engineering has not released any statement addressing whether the recalled connecting-rod defects could affect oil pressure at the lifter galley. The unnamed supplier has likewise remained silent. Until one or both parties publish root-cause findings, the relationship between the two failure modes will stay in the realm of informed speculation by technicians rather than established engineering fact.
Fleet managers who operate large numbers of Silverado and Sierra trucks face a practical decision right now. Recall 25V-274 obligates GM to repair or replace engines with the documented connecting-rod and crankshaft defects, but it does not automatically cover unrelated lifter failures. For fleets, that means carefully documenting symptoms, service histories, and mileage when problems arise, so that any overlap with the recall conditions can be clearly presented at the dealership.
Individual owners should start by checking whether their truck is included in the recall and monitoring for warning signs of both issues. Early indicators of lifter trouble can include intermittent ticking noises, misfires under light load, rough idle when the engine transitions between four- and eight-cylinder modes, and an illuminated check-engine light with cylinder deactivation-related codes. Drivers experiencing sudden loss of power, metallic knocking, or oil-pressure warnings should shut the engine down as soon as it is safe to do so and arrange for a tow, as continued operation can turn a repairable failure into a full engine replacement.
Owners who suspect related problems but fall outside the recall coverage can still file complaints with NHTSA. Those reports help regulators understand whether the current preliminary evaluation should expand, and they create a paper trail if additional recalls or service campaigns are later announced. Keeping copies of repair invoices, diagnostic notes, and oil-change records can also strengthen any goodwill request to GM for out-of-warranty assistance.
What comes next for L87 truck reliability
For now, the engineering story of the L87’s failures is incomplete. Regulators are investigating sudden engine shutdowns, GM is replacing engines with confirmed connecting-rod and crankshaft defects, and independent mechanics are rebuilding top ends damaged by collapsed lifters. Whether these threads ultimately converge into a single root cause or remain separate problems will depend on what NHTSA’s evaluation and GM’s internal analyses eventually reveal.
In the meantime, Silverado and Sierra owners are left to manage risk rather than certainty. Staying current on recall notices, responding quickly to new noises or drivability changes, and insisting on thorough documentation at the service counter are the most practical steps available. If future findings show that lifter failures and connecting-rod defects share a common origin, today’s records will be critical in determining who pays for tomorrow’s repairs.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
