The General Motors L87 6.2L V8: Design, Reliability Issues, Failure Modes, and Repair Strategies
The General Motors L87 is a 6.2-liter gasoline V8 belonging to GM's modern small-block engine family. Introduced in the latest generation of full-size GM trucks and later expanded into full-size SUVs, the L87 was designed to combine the traditional torque and simplicity associated with a pushrod V8 with modern technologies intended to improve power, efficiency and emissions. It has become one of General Motors' most recognizable premium truck engines, appearing in vehicles such as the Chevrolet Silverado 1500, Tahoe and Suburban, GMC Sierra 1500, Yukon and Yukon XL, and Cadillac Escalade.
On paper, the L87 is an impressive engine. General Motors rates it at 420 horsepower at 5,600 rpm and 460 lb-ft of torque at 4,100 rpm. Displacement is 6,162 cc, compression ratio is 11.5:1, and the engine retains a two-valve-per-cylinder overhead-valve configuration. Modern features include direct fuel injection, variable valve timing, oil-jet piston cooling, a two-stage oil pump, hydraulic roller lifters and Dynamic Fuel Management, or DFM. GM describes the L87 as an evolution of the earlier L86 6.2-liter V8, adding provisions for automatic start/stop and the more sophisticated DFM cylinder-deactivation system.
Despite its strong power output and fundamentally proven small-block architecture, the L87 has developed a complicated reliability history. Several distinct problems have been documented by General Motors through service bulletins, customer-satisfaction campaigns and, most significantly, a major federal safety recall involving crankshaft, connecting-rod and bearing failures. Understanding these problems is important for owners, technicians and anyone considering the rebuilding or remanufacturing of the L87.
Crankshaft, Connecting-Rod and Bearing Failures
The most serious L87 reliability concern involves the engine's crankshaft, connecting rods and bearings. In 2025, General Motors recalled certain 2021-2024 vehicles equipped with the L87 because manufacturing defects could result in internal engine damage and eventual engine failure. The recall covers selected Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Tahoe and Suburban, and GMC Sierra 1500, Yukon and Yukon XL models. GM reported 597,630 potentially involved vehicles and estimated that approximately 3 percent of the recall population contained the defect.
Importantly, GM's investigation identified two specific manufacturing-related root causes rather than simply describing the engines as suffering from generic bearing wear. The first involved sediment or contamination associated with connecting rods and crankshaft oil galleries, which could damage connecting-rod bearings. The second involved crankshafts with dimensions and surface finishes outside specification. Either condition could compromise the oil film separating the bearings from the crankshaft journals, eventually causing bearing damage, increased friction, knocking, seizure or catastrophic engine failure.
The size of the investigation illustrates why the issue became so prominent. GM reported 28,102 U.S. field complaints or incidents potentially associated with L87 crankshaft, connecting-rod or bearing failures, including 14,332 allegations involving loss of propulsion. These numbers represent potentially related field reports rather than a confirmed count of defective engines, but they demonstrate that the problem was substantial enough to trigger an extensive investigation and safety recall.
Warning signs can include knocking, banging or other abnormal engine noises, a check-engine light, hesitation, unusually high engine speed, abnormal shifting, reduced propulsion or a no-start condition. Earlier GM technical information concerning seized or noisy L87 engines also directed technicians to inspect the engine oil and filter for metallic bearing material and, when debris was found, remove the oil pan and inspect the connecting-rod and main bearings.
The resolution depends on the condition of the particular engine. Under the recall procedure, affected engines are inspected and engines that do not pass the prescribed test are repaired or replaced as necessary. Vehicles that pass receive higher-viscosity engine oil, a new oil filter, a revised oil-fill cap and updated owner information. GM specifically states that the thicker oil provides an additional level of protection.
For engines actually damaged by the manufacturing defect, replacement is the more comprehensive solution. GM states that crankshafts and connecting rods used in repaired or replacement engines were produced after the suspect supplier manufacturing period. The company also reported that manufacturing improvements addressing contamination and dimensional/quality issues had been implemented on or before June 1, 2024.
GM additionally established special coverage for qualifying engines that experience failure as a result of this specific crankshaft/connecting-rod condition. The coverage extends to 10 years or 150,000 miles from the vehicle's original in-service date, whichever comes first, for qualifying vehicles after completion of the applicable field action.
Improper Main-Bearing-Cap Bolt Torque
Separate from the broader crankshaft recall was a much smaller 2022 customer-satisfaction program involving certain L87 engines whose inner main-bearing-cap bolts were not properly torqued during assembly.
Proper main-cap clamping force is essential because the main bearings support and locate the crankshaft. Incorrect fastener torque can affect bearing alignment and oil clearances and can contribute to a loss of oil pressure and eventual internal damage.
GM's campaign covered only a very small group—46 U.S. vehicles according to the bulletin—but it is significant from an engine-building standpoint because the approved correction was complete engine replacement rather than simply retorquing the existing fasteners. GM stated that affected engines could experience low engine-oil pressure and potentially suffer engine damage.
For anyone rebuilding an L87, the lesson is straightforward: main-bearing clearances, fastener condition and main-cap torque procedures are critical. A properly remanufactured engine should have crankshaft dimensions verified, bearing clearances measured rather than assumed, and all critical fasteners installed according to the appropriate torque and angle procedures.
Dynamic Fuel Management Lifter Problems
Another widely discussed area of L87 reliability is its valvetrain, particularly its Dynamic Fuel Management system.
Unlike the older Active Fuel Management system, which normally deactivated a predetermined group of cylinders, DFM can deactivate different combinations of cylinders depending on operating conditions. GM explains that DFM can alter cylinder firing patterns from one engine cycle to another in an effort to optimize efficiency. On the L87, this requires electronically controlled oil pressure and specialized hydraulic lifters capable of switching between normal valve operation and cylinder deactivation.
That complexity introduces additional potential failure points.
GM has documented conditions involving ticking noises, misfires, bent pushrods and collapsed lifters. In one technical bulletin covering the L87 and other GM engines, technicians are instructed to isolate the affected cylinder, inspect the pushrod and lifter, and replace the affected bank of lifters when a collapsed lifter is identified and the pushrod remains serviceable. The same bulletin identifies insufficient lifter oil during cold starting as one possible cause of ticking.
A failed or partially collapsed lifter can prevent the corresponding valve from following the camshaft correctly. Symptoms may include a repetitive ticking noise, rough idle, reduced power, a flashing or illuminated check-engine light and cylinder-specific or random-misfire codes. If the problem is driven long enough, damage can progress beyond the lifter. A damaged lifter roller can affect the camshaft lobe, while improper valve motion can bend a pushrod.
Repair therefore requires more than automatically replacing one noisy part. The lifters, guides, pushrods and corresponding camshaft lobes should be inspected as a system. GM's service information for related lifter failures specifically instructs technicians to inspect both the lifters and camshaft for excessive wear and replace damaged components as necessary.
For an engine being comprehensively rebuilt, replacing questionable lifters and inspecting the entire valvetrain before assembly can prevent a relatively inexpensive valvetrain defect from damaging an otherwise sound engine.
Valve-Spring Failures
Certain early L87 engines also experienced documented valve-spring failures. GM issued a service update covering specific 2020-2021 Silverado and Sierra models and certain 2021 Escalade, Tahoe, Suburban and Yukon vehicles equipped with the L87.
A broken valve spring may cause rough running, ticking or knocking, misfires, a check-engine light or even an engine stall.
The severity depends on what happens after the spring breaks. If the valve remains properly positioned and a cylinder-leakage test confirms that the valve and combustion chamber have not been damaged, replacing the affected spring may be sufficient. GM technical guidance also instructed technicians in certain early-production circumstances to replace all valve springs on qualifying low-mileage 6.2-liter engines. If the broken spring allows the valve to contact the piston or otherwise causes leakage or internal damage, additional cylinder-head or engine repair becomes necessary.
For a remanufactured L87, valve springs should therefore be treated as measurable wear and fatigue components rather than automatically reused. Spring pressure, installed height, physical condition and compatibility with the camshaft and valvetrain should all be verified.
Coolant Entering the Cylinders and Cold-Start Misfires
Some L87 engines have also been covered by GM diagnostic information concerning cold-start misfires, rough operation and coolant entering a combustion chamber.
GM Bulletin 20-NA-166 addresses conditions including P050D and P0300 codes, cold-start misfires and rough running. Potential causes include injector problems, but GM also identifies possible internal coolant entry at the cylinder-head casting or at the liner-to-deck area of the block. Diagnosis can involve cooling-system dye, pressure testing and borescope inspection after the engine has cooled.
The correct repair depends on the leak location. A cylinder-head casting problem can require replacement of the affected cylinder head. If coolant is entering at the cylinder liner-to-deck area, replacing the head alone will not correct the problem and engine replacement may be required under GM's documented procedure.
This is particularly relevant when remanufacturing an L87 because a rebuild should not focus exclusively on rotating components. Cylinder heads and block sealing surfaces should be pressure-tested and inspected for porosity, cracks, distortion and evidence of previous coolant intrusion.
Engine Oil Cooler Line Leakage
Certain 2019 Silverado and Sierra models were also included in a program addressing engine-oil-cooler lines that could leak or separate from their crimp joints, particularly in cold climates. If a line detached while the engine was operating, oil pressure could fall rapidly. Continued operation under those circumstances could damage the engine or result in loss of propulsion.
GM's correction was replacement of the affected oil-cooler hose assembly together with engine oil and filter service.
Although this problem involves an external component rather than an internal design defect, it demonstrates an important principle: many catastrophic engine failures begin with loss of lubrication rather than a broken internal component. Any replacement or remanufactured L87 should therefore be installed only after the external oiling system, cooler circuit and related hoses have been inspected.
Oil Consumption and Lubrication
Some oil consumption is normal in any internal-combustion engine, and it is important not to misdiagnose normal consumption as an L87 defect. GM's general oil-consumption guidance identifies one quart per 2,000 miles as its accepted threshold under specified light-duty warranty test conditions, while noting that towing, high engine speeds, aggressive driving and other operating conditions can increase consumption. GM also directs technicians to consider external leaks, PCV-system problems, oil dilution, piston-ring problems and cylinder wear when diagnosing excessive oil usage.
For L87 owners, maintaining the proper oil level is particularly important given the engine's hydraulic lifters, variable valve timing, two-stage oil pump and known history of bearing-related failures. Low oil level should never be treated as a harmless inconvenience.
Building a More Reliable L87
The L87's reliability history does not mean that every 6.2-liter engine will experience these problems. Several issues were confined to particular production windows, specific component populations or relatively small groups of vehicles. Nevertheless, the documented failures provide an unusually useful blueprint for improving the engine during professional remanufacturing.
A thoroughly rebuilt L87 should receive careful crankshaft inspection and measurement, verified connecting-rod and main-bearing clearances, meticulous cleaning of every oil passage, proper main-cap fastener installation, inspection or replacement of vulnerable valvetrain components, camshaft inspection, valve-spring testing, cylinder-head and block pressure testing, and verification of the oil pump and lubrication system. Any engine that suffered a previous bearing failure should also be inspected carefully for metallic debris throughout the lubrication circuit.
The L87 remains an exceptionally capable engine architecture. Its 420 horsepower and 460 lb-ft of torque, compact pushrod design, aluminum construction, direct injection and variable valve timing make it well suited to demanding full-size trucks and SUVs. Its known weaknesses are also increasingly well understood.
That knowledge is valuable. Rather than simply replacing failed components with identical parts and returning an engine to service, a comprehensive rebuilding process can address the causes behind the failures: contamination, incorrect clearances or surface finishes, inadequate component inspection, valvetrain wear, questionable valve springs, sealing problems and lubrication-system concerns.
When those areas are inspected methodically and corrected during the manufacturing process, the goal is not merely to restore an L87 to operating condition. It is to produce an engine in which the known weaknesses of the original application have been specifically examined and addressed—creating the foundation for the durability, smooth operation and long service life that owners expect from a premium 6.2-liter V8.
