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The check engine light was just the beginning of a nightmare for Matthew Scharenberg, whose meticulously maintained 2020 GMC Sierra was declared a complete engine failure, leaving him with a $15,000 repair bill.
Matthew Scharenberg on the 2019 – 2025 Chevy Silverado & GMC Sierra Owners Facebook page says,
“Hey, everyone! I am the owner of a 2020 GMC Sierra 1500 equipped with a 5.3-liter engine. I had 77,000 miles on it and had it serviced all the time by the dealer I bought it from. Anyway, my check engine light came on about a month ago, and I couldn’t find anything.”
“Now, my low engine oil light has come on.”
“They are now calling it a complete engine failure and say this is a $10,000 to $15,000 job. I know the 5.3 had issues back in like 2014 or so. Has anyone else had any 5.3 motor issues on a 2020?”
Imagine owning this GMC pickup, and just 77,000 miles in, it has a catastrophic engine failure. It’s out of warranty, and the dealership’s repair estimate is $10,000 to $15,000. That’s money you could put down on a new truck, but your truck is worthless without a new engine.
This specific account of a 2020 GMC Sierra 5.3L engine failure at 77,000 miles is far from an isolated incident; it’s a symptom of a much larger, systemic problem plaguing General Motors’ flagship V8 engines.
For years, the 5.3L V8 has been a stalwart of the GM truck and SUV lineup, prized for its reliability and balanced performance. However, with the introduction of new fuel-saving technologies, this reputation has come under fire.
The Gen V EcoTec3 engine, introduced in the 2014 model year, incorporated a cylinder deactivation system initially known as Active Fuel Management (AFM), which later evolved into Dynamic Fuel Management (DFM) for the 2019 model year and subsequent years. Both systems are designed to deactivate certain cylinders under light load conditions to improve fuel economy. While the intention is to help consumers save money at the pump, these complex systems have proven to be the Achilles’ heel for many owners.
The central component most often cited in these catastrophic failures is the hydraulic roller lifter.
The DFM system uses a special lifter that can collapse to disengage the pushrod and close the valves on the deactivating cylinders. This constant switching between four-cylinder and eight-cylinder modes puts immense stress on these components. Reports from owners and independent mechanics alike reveal that these lifters can fail, causing a cascading series of events.
A failed lifter can seize or break, leading to a bent pushrod, a damaged camshaft, or even debris entering the oil system, which can cause total engine seizure. The tell-tale signs often begin with a subtle ticking or knocking noise from the engine, followed by a flashing or solid check engine light due to a misfire. This is a primary contributor to the common problems with 2020 5.3L V8 GMC Sierra trucks.
The sheer financial devastation of such a failure is what makes Matthew Scharenberg’s story so impactful.
The dealership’s quote of up to $15,000 for a new engine is a grim reality for many who find themselves out of warranty. The cost to repair the complete failure of the GM 5.3L engine is a significant burden, often forcing owners into a difficult choice: pay for a new engine that could be susceptible to the same issues, sell the vehicle at a substantial loss, or attempt an aftermarket fix.
A brand-new or remanufactured engine can easily run over $8,000 for the part alone, with labor adding thousands more. For a truck just a few years old, this is an unacceptable expense, especially when the failure seems to stem from a known design flaw.
This is not just a handful of isolated cases; a quick search through online forums and news sites reveals a broader crisis of confidence. Discussions surrounding Chevy Silverado 5.3L engine problems, particularly for the 2020 model year and beyond, are prolific. A class-action lawsuit filed against GM over these lifter issues highlights the scale of the problem. While the lawsuit is ongoing, it confirms that GM has long been aware of the alleged defect.
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The National Highway Traffic Safety Administration (NHTSA) has also launched an investigation, prompting GM to issue recalls for some vehicles with similar engine issues, though not always for the specific 2020 5.3L model. Owners are left to wonder if GM will ever take comprehensive responsibility.
For many owners, the frustration is compounded by the fact that they have followed the service schedule meticulously. As Scharenberg stated, his truck was “serviced all the time from the dealer.” This raises a critical question: Why did my GMC 5.3L engine fail at such a low mileage, despite diligent maintenance? The answer points back to the inherent vulnerabilities of the DFM system.
The issue isn’t always about neglect; it’s about the design.
The system’s intricate oil flow requirements and the constant stress on components make it prone to failure, regardless of how often the oil is changed. This is also why many owners are concerned about Active Fuel Management issues in 2020 GMC Sierra vehicles, as it is the leading theory behind the failures.
Given the widespread nature of the problem, owners are seeking solutions. Many are opting for aftermarket “AFM/DFM disabler” devices that plug into the OBD-II port, preventing the system from ever deactivating cylinders. Others, facing a complete engine replacement, are choosing to “delete” the DFM system entirely by installing a non-DFM camshaft, new lifters, and a custom tune.
While these options void the manufacturer’s warranty, many owners feel it’s a necessary step to ensure the long-term health of their vehicles. For a consumer who asks, Is GM covering engine repairs for 2020 5.3L failures?, the answer is often disappointing.
Outside of the standard powertrain warranty, GM’s assistance is on a case-by-case basis, often requiring persistent communication with corporate customer service. This leaves many owners stranded, facing a substantial repair bill due to a known manufacturing defect.
This crisis of quality control is a stark reminder that even a beloved engine, when integrated with overly complex technology, can become a liability. The onus is on the manufacturer to address the root cause, rather than leaving a trail of disappointed and financially burdened customers in its wake.
In The End
As a senior reporter, my role is to provide a voice for the issues that impact consumers, and in this case, the stories from countless truck owners, like Matthew Scharenberg, are screaming for attention. The catastrophic failure of a modern truck’s engine at just 77,000 miles, with all due diligence in maintenance, is unacceptable. It’s a crisis of trust between a brand and its loyal customers.
While GM is a monumental company with a history of building durable vehicles, this ongoing saga with the 5.3L V8 engine, and its DFM system in particular, is a significant stain on its reputation. It’s time for a more comprehensive, uniform solution that doesn’t leave owners to fend for themselves with repair bills that rival a year’s salary. Until then, the community forums and social media pages will continue to be filled with the lamentations of those who were sold a dream of reliability that turned into a nightmare of costly repairs.
Questions For GMC Sierra Owners
Have you experienced any of the common warning signs of DFM/AFM lifter failure, such as a ticking/knocking noise or a flashing check engine light, before a major engine issue occurs? If so, what was your truck’s mileage at the time, and what was the ultimate cause of the failure as diagnosed by a mechanic or dealership?
What actions, if any, have you taken to prevent or address potential DFM/AFM issues, such as using an AFM/DFM disabler device, performing more frequent oil changes, or pursuing a “DFM delete”? How has the manufacturer or dealership responded to your concerns about these known issues, and what was the outcome (e.g., covered by warranty, out-of-pocket repair cost, or no resolution)?
Click the red Add New Comment link below and let us know.
Check out my GMC Sierra story: I Bought a 2025 GMC Sierra and With Only 100 Miles I Had It Towed To the Dealer, The Engine Is Making A Horrible Death Rattle
I am Denis Flierl, a Senior Torque News Reporter since 2012. My 30+ year tenure in the automotive industry, initially in a consulting role with every major car brand and later as a freelance journalist test-driving new vehicles, has equipped me with a wealth of knowledge. I specialize in reporting the latest automotive news, covering owner stories, and providing expert analysis, ensuring that you are always well-informed and up-to-date. Follow me on X @DenisFlierl, @WorldsCoolestRides, Facebook, and Instagram
Photo credit: Denis Flierl
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Source: torquenews.com
