A 17-year active-duty Marine stationed at Camp Pendleton took to Reddit in April to share a troubling experience with his 2021 GMC Yukon XL Denali with a 6.2L V8. Just over a month after the engine was replaced due to oil consumption issues, he says it failed again.

This time, it happened while his wife and four children were driving on the freeway. The vehicle lost power in the middle lane of California’s I-215.

The family originally bought the Yukon in 2023. Reportedly, it developed oil consumption issues by early 2025, prompting the GMC dealer to replace the engine. Barely a month later, the Redditor says that the new engine failed catastrophically.

Warning lights came on, the engine began to clank, and then the SUV lost all power, all while moving at highway speeds. The Marine said he had to run into traffic to push the disabled vehicle to safety. No one was hurt, but the situation could have gone very differently.

Since then, things have only gotten worse. The family paid for two tows, rented a vehicle too small for six people, and learned that a replacement engine is backordered for four months. 

According to the Marine, GM hasn’t offered meaningful help. He says he’s written to company leadership, spoken to multiple dealers, and kept meticulous service records. Still, the family remains stuck with an expensive SUV they don’t trust to drive.

So, is this just one unlucky GMC vehicle, or part of a larger issue?

Unfortunately, engine troubles in General Motors’ full-size SUVs and trucks aren’t unheard of. 

The 2021 GMC Yukon uses GM’s 6.2-liter V8, part of the “L87” family of small-block engines. While powerful and refined, this engine series has seen complaints about lifter failures, oil consumption, and in rarer cases, total engine failure. 

A growing number of owners have shared stories online about major engine issues within the first 50,000 miles.

GM has issued technical service bulletins and, recently, a recall for 600-some-odd-thousand units. Up until this point, though, many owners, like this Marine, left dealing with expensive repairs, long wait times for parts, and what they describe as a lack of urgency from the automaker. Seems like this 2021 GMC Yukon is another statistic, but the Marine is hoping GM’ll do better moving ahead.

The automaker just announced a huge $888 million investment in its Buffalo, NY plant, specifically aimed at the incoming sixth-gen V8. The new engine is slated for 2027 models.