2021 GMC Sierra 6.2 Engine Failure: Understanding Your Options

If you drive a 2021–2024 GMC Sierra equipped with the 6.2 L L87 V‑8, you may have grounds for a lemon law claim. Reports of sudden power loss, loud knocking, or complete engine shutdown have prompted both a national safety investigation and a recall of nearly 600,000 vehicles.

Here’s what’s behind the 2021 GMC Sierra 6.2 engine failure recall and how we can help you pursue the compensation you deserve.

Table of contents

• Why Is There a Recall on the 2021 GMC Sierra?
  
• Signs of Failure in the GM Sierra 6.2 Engine
• Steps to Take if You Have Engine Failure
  
• Let a Lemon Law Attorney Help You
  
• FAQ
  

Why Is There a Recall on the 2021 GMC Sierra?

GM issued a voluntary recall (NHTSA Campaign 25V274000) in April 2025 after widespread reports of dangerous engine failures in 2021–2024 half-ton trucks and large SUVs equipped with the 6.2 L L87 V‑8. The recall affects the following models: Sierra, Chevy Silverado, Tahoe, Suburban, Yukon, Yukon XL, Cadillac Escalade, and Escalade ESV.

GM expects approximately 3% of these engines to fail inspection and require complete replacement, affecting thousands of owners who purchased vehicles they believed were reliable.

Manufacturing Defects

The 2021 GMC Sierra’s 6.2 engine failure issue stems from confirmed manufacturing defects in the connecting rods and crankshaft components, as documented in GM’s April 2025 recall (NHTSA Campaign 25V274000). Improper crankshaft machining, incorrect dimensions, or contamination in the connecting rod bearing surfaces can lead to catastrophic internal damage. These flaws may cause the engine to suddenly lose power, seize, or fail entirely without prior warning.

Although some vehicle owners have also reported problems involving lifters or valve components, GM has stated that these are not part of the current recall and are not considered contributing causes of the documented safety defect.

Oil Circulation and Component Damage

In engines affected by the recall, oil starvation can occur due to bearing wear or debris obstructing oil passages, leading to rod bearing failure.

Some owners have also observed low oil pressure warnings; however, GM’s official recall does not identify a flaw in the oil pump design or pressure regulation system.

Owner-Reported Carbon Buildup (Not Part of Recall)

Some owners of GM’s 6.2 L L87 V8 engines have reported carbon buildup on intake valves, which may result in performance issues like misfires or reduced power. However, this issue is not related to the 2025 recall and is not cited by GM or NHTSA as a safety defect. These buildup issues are commonly associated with direct injection engines and are considered maintenance-related, not manufacturing defects.

Gasket Wear (Unrelated to Recall)

Over time, some owners have reported intake manifold gasket leaks in GM 6.2 L engines, which may cause poor idling or triggering of warning lights. However, these issues are considered age-related wear and are not part of the 2025 recall. There is no evidence that gasket leaks contribute to the engine failures caused by crankshaft or rod-bearing defects as described in the recall campaign.

Exhaust Bolt Issues (Unrelated to Recall)

Failed exhaust manifold bolts create exhaust leaks that increase backpressure and trigger check engine lights or misfires. These leaks worsen your vehicle’s performance problems and can damage oxygen sensors and catalytic converters. While less common than other 6.2L engine issues, exhaust bolt failures add another layer of stress to an already problematic engine design.

Although exhaust manifold bolt failure has been reported in some GM 6.2 L engines, this issue is not linked to the April 2025 engine recall. These failures may cause exhaust leaks or performance problems but are considered separate from the connecting rod and crankshaft defect responsible for engine seizure or shutdown in recalled models.

What Are the Signs of Failure in the GM Sierra 6.2 Engine?

Even if your engine hasn’t failed entirely, these warning signs can alert you to underlying problems:

Unusual Noises

Knocking, tapping, or grinding sounds may indicate issues with the lifters, valvetrain, or pistons. These noises often signal excessive internal wear and should be addressed immediately to prevent further damage.

Performance Issues

You might notice hesitation, sluggish acceleration, or reduced towing power. These symptoms can stem from improper combustion or failing engine components, such as the camshaft or intake valves.

Check Engine Light

Take any illuminated check engine light seriously, even if your truck seems to run normally. This warning often indicates critical problems with oil pressure, engine timing, or other vital systems.

Oil Pressure Issues

Low oil pressure messages or dashboard warnings can result from clogged oil passages, faulty pumps, or worn lifters. Driving with low oil pressure can lead to irreversible engine damage quickly.

Engine Stalling or Shutdown

Some drivers report their Sierra shutting down unexpectedly, even at highway speeds. This serious issue poses a safety risk and is often related to severe fuel or ignition problems.

Engine Seizure

In extreme cases, the engine may seize entirely, often preceded by a loud bang or metallic snap. When this occurs, internal components may be damaged or fused together, typically requiring a complete engine replacement.

These warning signs shouldn’t be ignored. If you’re experiencing any of the above, prompt inspection and thorough documentation are critical steps in protecting your vehicle and preserving your Lemon Law rights.

Steps to Take if You Have Engine Failure With Your 2021 GMC Sierra 6.2

Take action early, even if your engine appears to be fine. When left unchecked, latent manufacturing defects can turn minor problems into major repairs.

Take Your Vehicle to the Dealership

The first step is to bring your Sierra into a GM dealership for inspection. The dealership will:

• Inspect the engine’s crankshaft and connecting rod bearing surfaces
• Determine if the engine shows signs of wear, misalignment, or contamination
• Replace the engine at no cost if internal damage is found

If the engine passes inspection, they will:

• Perform an oil and filter change using Mobil 1 0W-40 Supercar oil
• Install a new oil fill cap and update the owner’s manual
• Enroll the engine in GM’s 10-year/150,000-mile extended coverage

Make sure to get copies of all repair orders and keep detailed records. This documentation protects your rights if the problems persist after GM’s repair attempts.

Refer to Your State’s Lemon Law

Lemon laws are state consumer protection statutes that require manufacturers to replace or refund defective vehicles when they cannot be repaired after a reasonable number of attempts. These laws typically cover new and recently purchased vehicles still under warranty—including 2021-2024 GMC Sierras experiencing engine failures.

To invoke lemon law protections, you must first give the manufacturer adequate opportunities to repair the defect through authorized dealerships. Each state defines “reasonable attempts” differently, but generally requires 3-4 repair attempts for the same problem or the vehicle being out of service for 30+ days. Given the complexity of these requirements, you may need legal representation to successfully navigate the process.

Let Our Lemon Law Attorneys Help You

Pursuing a lemon law claim against a major manufacturer like GM requires legal experience. An experienced attorney can evaluate your repair history, determine if your case meets state requirements, and handle complex negotiations with GM’s legal team. Manufacturers often resist lemon law claims, making professional representation essential.

Our team at Timothy Abeel & Associates has extensive experience helping vehicle owners secure refunds, replacement vehicles, or cash compensation for defective cars. We handle all aspects of your case at no cost to you—GM pays our legal fees when we win.

Time is of the essence. Get your free case review today to protect your rights and explore your options.

FAQ