GM’s 6.2-Liter V8 Is Seizing Up At Highway Speeds And Leaving Owners Stranded

GM has a problem engine on its hands. The automaker’s 6.2-liter gasoline V8 is now under the magnifying glass. As reported by Reuters, NHTSA has launched a preliminary probe into over 870,000 GM vehicles equipped with the engine amidst reports of major failures in the field.

The engine in question is formally known as the L87, and branded as the EcoTec3. It comes from the broader LS small block engine family, and is effectively an LT1 engine that has been reconfigured for truck applications. It delivers 420 horsepower and 460 pound-feet of torque. It’s a modern and complicated engine, featuring variable valve timing, cylinder deactivation, and even a variable pressure oil pump. The direct successor of the earlier L86, it was first launched in 2019, and appears in a wide range of GM trucks and SUVs.

Reports received by NHTSA indicate that L87 engines built from 2019 onwards are suffering bearing failure with major consequences. Complaints indicate that the engines may seize, or, in extreme cases, eject connecting rods through the engine block. It’s no small problem, with over 877,000 vehicles potentially affected. Let’s explore what’s going on.

On The Ground

The 6.2-liter L87 is one of GM’s main workhorses, featured across a number of trucks and SUVs. It debuted in the Chevrolet Silverado 1500 and the GMC Sierra 1500 in 2019. It’s also found in the Chevy Suburban and Tahoe, the GMC Yukon, and the Cadillac Escalade.

Across all these vehicles, owners have found themselves suddenly facing a total loss of power when driving, only to later find out that major engine damage has occurred. The problem doesn’t seem to be limited to any one model year or model; instead, it seems to affect a range of vehicles with the L87 engine built from 2019 until today.

It doesn’t take a genius to know that a sudden engine failure can leave you in a dangerous situation.  The agency notes the severity of the problem, and the inherent safety risks—explaining that “Failure or malfunction of the engine results in loss of motive power of the vehicle, which may lead to an increased risk of a crash resulting in injury and/or property damage.” Thankfully, as of yet, no crashes, injuries, or fatalities are known to have occurred.

As it stands, NHTSA has received 39 complaints regarding the matter, with submissions stretching back several years. Submissions to the agency indicate the problems often tend to crop up suddenly, without prior warning. At best, some owners hear strange noises or ticking, or get a warning for low oil pressure as the engine seizes up. In some cases, the issues have occurred in trucks with under 5,000 miles on the clock, with NHTSA recording multiple cases of total engine failure under 20,000 miles. However, some vehicles have approached 100,000 miles before failure.

Interestingly, some owners cite that their problems first became apparent when the vehicle suddenly shifted into neutral, only for them to later find the true issue to be major engine damage. Others have found they are able to restart their vehicles after an initial loss of power, only for the problem to reoccur. Most cases, however, seem to involve a single sudden incident where the engine loses power and totally seizes up.

In many cases, the engine has suddenly failed while owners are traveling at highway speeds, leaving them with zero power in a dangerous situation. “While driving on a busy road our vehicle stopped from catastrophic engine failure without warning which put my family and I instantly in danger and nearly got us killed,” stated one shaken owner. “Due to the high traffic where it stopped we were scared to stay in the vehicle and also scared to exit it, so we contacted the police before calling a tow truck.”

In cases cited by the NHTSA probe, post-incident inspection typically reveals telltale signs of engine bearing failure. One complainant notes that “while traveling at highway speeds, the vehicle suddenly and without warning lost power.” Upon pulling off the road, the engine would not restart, so the vehicle was towed to a dealership for repair. “While inspecting, dealership found internal engine bearing material in oil indicating internal mechanical failure,” reads the complaint. “Dealership removed engine oil pan and #1 and #2 connecting rods and found bearings spun causing catastrophic engine failure.”

Customer's 2023 6.2L Silverado with 28k shut off going down the road. Pan full of glitter, one damaged main bearing, three spun rod bearings.
byu/N_dixon inJustrolledintotheshop

Just knocked into the shop. 2022 GMC Sierra 1500 with the 6.2L, spun and stacked the #1 rod bearing at 15,783 miles
byu/N_dixon inJustrolledintotheshop

2023 Sierra Denali 6.2. You know it’s bad when you can see the top of cylinder 6 piston from underneath the truck.
byu/gmlubetech inJustrolledintotheshop

Horror pictures of seized 6.2L engines have started showing up in the usual places online.

Others have had even worse luck. One owner was out camping when disaster struck. “We were approximately 30 minutes out of town when the engine blew… [we] lost all electronics and had to drive off to the side of the road.” reads their complaint. Their vehicle was towed to a dealer in Arizona and  fitted with a new engine, only for lightning to strike twice. “After 10 minutes of running, the new engine seized as well,” the owner told NHTSA. “My vehicle has been down for over 30 days and I still do not have it back.”

Head out on to the open Internet, and you’ll find plenty more stories along the same lines. Over on the Silverado Sierra forums, owners complain of engines suddenly seizing up, and problems with sorting out replacements under warranty.  Meanwhile, on the Tahoe Yukon Forum, the story is much the same. “Have had my 2023 Yukon Denali for 9 months and broke down on [the] side of [the] road,” says Muzbomb, an owner up in Canada. “Towed to dealer and [was] informed today [the] main bearing on [the] 6.2L went.”

Another 2023 GM 6.2l Failure 2,049 miles
byu/Fast_Site7131 ingmc

Stories like this are easy to find.

Unknowns

At this stage, the root cause of the problem is unknown. Something is causing connecting rod bearing failures that are seizing up these engines. But precisely why these bearings are failing is unclear. What we do know is that some engines have failed at incredibly low mileage, and some owners have suffered multiple failures after engine replacements. This would hint towards a design flaw, rather than some minor or intermittent materials or manufacturing issue.

However, without a full engineering analysis, it’s impossible to say with any certainty what the cause could be at this stage. Nor is it clear how many vehicles are affected amongst the total population of over 870,000 vehicles with the 6.2-liter engine.

GM has issued bulletins regarding the matter. As published via TechLink, a platform for GM techs, the document concerns investigating bearing damage in L87 engines with a no-crank condition. It instructs techs to look for bearing material and other metal debris in the oil filter. It also contains several images indicating what to look for when diagnosing bearing failure. A bearing covered in scoring marks or chunks of metal is the key tell-tale sign.

In the case of bearing failure, a total engine replacement is indicated. GM has also specified that it is important to fully replace other components in the lubrication circuit too, in order to ensure metal debris is not immediately introduced into the replacement engine. As per the bulletin:

If the main bearing debris is sent through the oil galleries and other components that are in the lubrication circuit, which are very difficult to completely clean, it could lead to additional damage when installed on a new engine. When there is extensive damage, oil cooler, oil cooler line and oil tank replacement ensures all debris is completely removed and that any bearing failure debris is not transferred into the new service engine.

-GM TechLink

The Autopian contacted GM enquiring as to the root cause of the issue, but a clear explanation is not yet available. “GM is cooperating with NHTSA’s evaluation to review the potential problem and fully assess the potential safety related issues,” said a GM spokesperson. Nor are there any obvious preventative measures to take at this stage. “As with any GM vehicle on the road today, we suggest owners follow prescribed maintenance schedules and resolve any issues or concerns with their local dealers.“

This isn’t the only issue the 6.2-liter V8 has suffered, either. Lifter issues have plagued the model for some time, becoming a hot topic on owner’s forums over the last few years. Owners have shared tales of noisy lifters and even bent pushrods, some of which failed after less than 20,000 miles. GM also issued a bulletin regarding certain 2023 models that received engines with oversized lifter bores, mandating engine replacement for affected models. These issues seem to be largely separate from the bearing failures now being investigated by NHTSA, but are nonetheless another black mark against the L87 engine.

Supply Woes

It appears the failures could be common enough to cause supply problems for GM. Evidence is anecdotal, but stories of long waits are becoming increasingly common. Owners on the r/gmcsierra subreddit reported wait times of several weeks in early 2024.

Commenters on GM Authority this week suggest that the situation is more dire. “I bought a 2025 Silverado ZR2 with the 6.2 liter engine, [and] the engine blew the bearing at 3000 km,” said owner Tim Weber. “They tell me it’s going to be three to six months for a new engine from the factory.” Some owners are being told that replacement engines are currently on backorder. Meanwhile, some dealers have apparently started stockpiling replacement engines and parts in order to execute repairs faster.

The Autopian reached out to GM for comment on availability, though the automaker was unable to provide specific details around the issue. “GM dealers continue to address customer issues on a case-by-case basis and work to resolve them as quickly as possible,” said a GM spokesperson.

GM Dealer Adventures: as my wait for an engine goes into its fourth week, I’ve been evaluating emergency options. Here are some observations.

1. Deny. Deny. Deny. Only one sales guy was straight up and real with me on the engine problems. If I buy a second vehicle it will be

— Chey Cab (@CheyCab) January 19, 2025

Some owners are complaining of long waits to get their trucks fixed under warranty.

More recently, luxury car fleet operator Chey Eisenman took to Twitter to complain of a wait exceeding four weeks. Speaking to The Autopian, the founder of Chey Car noted that the 6.2 issues have reached a critical juncture. “I own one limo licensed vehicle and it’s currently not in service needing a 6.2 engine, a 2023 Cadillac Escalade ESV,” Chey explained. “GM has no ETA and I’ve been calling them nearly every day.”

Chey has noticed that the lifter issues have dominated in the transport industry, rather than the bearing problems. “Most of us having issues are the lifters going out and the metal particles contaminating the engine,” she says. ” There’s also reports of engines seizing up but our industry hasn’t experienced that yet that I know of.”

Ultimately, most luxury fleet operators take steps to avoid these issues, but it’s not working in this case. ” It’s unprecedented for us to have to do engines in our vehicles,” she says. “We buy new and trade out every 1-2 years.” Despite this, she reports seeing these engines go out with as little as 6,000 to 30,000 miles on the clock. The impact on the financial side is what hurts most for her operation, as she’s losing revenue as long as the vehicle is out of action. “I can’t articulate enough the hardship on my business,” she explains, noting the losses will likely stretch well into the five figure range.

Going Forward

It’s ultimately a difficult situation for GM and customers alike. At this stage, it’s unclear whether the 6.2-liter engine has a fundamental design flaw, or whether there’s a manufacturing issue at play, or something else entirely. Until the root cause of the problem is understood, GM can do little more than replace engines and hope for the best. The fact that several owners have reported engines failing after replacement suggests that the issue is still poorly understood.

If you’ve got a GM vehicle with the L87 engine under the hood, cross your fingers that it avoids this nasty calamity. Beyond sticking to the recommended maintenance schedule, it seems there is no clear way to prevent this problem at this time. Engine replacements may be hard to come by if reports from the ground are accurate, so don’t expect a quick fix at this time.

Image credits: GM

Support our mission of championing car culture by becoming an Official Autopian Member.

• Why So Many People Hate Chrome-Capped Lug Nuts

• Here’s Why Busted Plastic Grille Flaps On A Newer Car Can Cause A Check Engine Light

• Some GM Trucks And SUVs Are About To Get Recalled For A Transmission Problem That Can Lock Up The Rear Wheels While Driving

• In The Midst Of An Investigation, NHTSA Wants More Information On Tesla Driver Monitoring Systems

• Here Are The Automakers That Recalled The Most Cars In 2024

Please send tips about cool car things to tips@theautopian.com. You could even win a prize!