2023 GMC Sierra engine problems

“My 6.2 motor in my 2023 GMC AT4 truck has blown up. As part of the recall that GM has on this motor it passed the "pico test" at around 50k miles or so ( I can provide the paperwork) and then this past week with 63k miles or so the engine developed a miss and eventually by the time I got it to the dealer there was a significant "engine knock". The service center called the next day and said there was definitely a engine failure and I was lucky to have made it to the dealer. The vehicle is at the dealer waiting on a new engine. I was quoted 2 weeks but we are passing that time frame now. GM needs to be held accountable for this mess.”

“My truck's engine failed in April 2026 and was replaced. Approximately 7,000 miles later, the replacement engine failed as well. After bringing the vehicle to the dealership for another engine replacement, the newly installed engine seized during the dealer's test drive before the repair could even be completed. As a result, I am facing additional delays and have been without a reliable vehicle for an extended period.”

“On XXX, at approximately 2:30am, about 30 hours after purchase, a 2023 GMC Sierra Denali Ultimate suffered catastrophic engine failure in [XXX] during a planned 20 hour trip. The vehicle had about 49,007 miles at purchase and 49,411 miles at the time of failure. The check engine light appeared during the trip. Over five hours into the journey, shortly after passing through a one-lane construction zone with no shoulder, the truck made noises, then lost driving power and began slowing among highway traffic. The dashboard displayed "LOW OIL PRESSURE STOP ENGINE," code P0016, and a transmission warning. I had to move into another lane to reach the shoulder. The sudden loss of propulsion at 2:30am created a serious crash risk because the truck could have been struck by nearby traffic or become disabled on the one-lane road without a shoulder. The engine had received the GM L87 recall remedy on XXX involving a change to 0W-40 oil. Despite this remedy, the engine failed while the vehicle was moving. The repair order lists replacements for the engine, radiator, oil cooler lines, intake manifold and gaskets, spark plugs and wires, water pump gaskets, high pressure fuel…”

“It is a 23 GMC Sierra Denali has the L87 [XXX].2 with 43,000 miles an blew up yesterday while on vacation in [XXX].”

“A 6.2 engine operated as expected for 75,000 miles. I turned a corner at an intersection, and had a loud knocking in the engine occur. For the first 75,000 miles, there wasn't any unusual engine noises or oil consumption.Seconds later the engine light illuminated on the dash, reduced engine power, and every safety light within the dash was going on and off. I managed to drive slow and return to my residence and have the truck towed to the dealership to have the engine replaced. As many have learned, the recall from GM states to either pass a PICO test and change to 0W-40, or have the engine replaced if necessary. My concern is that the replacement engine is the exact same engine with the exact same components that assuredly will fail due improper design, production, and overlooked components that attribute to such failure. The crankshafts are being found to have values of "peaks and troughs" within the finish that are many times out of given specifications. The extraneous pressures created by the Dynamic Fuel management system over time are creating stresses and friction that the designated oil and oil pump are not compensating for. These mechanical stresses…”

“1) Driving on highway and lost acceleration power would only go 50 mph/went into limp mode. Dealership stated VIN number had not been released into national safety recall. Replaced crank shaft valve and was told once VIN was released I would be reimbursed, to date still in dispute. 2) low oil light came on, upon checking oil was extremely low and oil had just been changed during #1’s repair. Had towed to dealership. Engine was replaced under recall. Was charged for water pump which is in dispute. 3) shortly after and well before oil change would be due, low oil light came on again. Towed back to dealership dip stick bone dry. I asked the store vehicle inside. Called for diagnosis at 5pm stated no codes no leaks found needed to investigate further. 4) 9am following day received a vm the truck had been repossessed by GM (note there is only 10K remaining on a special order 72K truck) dealership has not responded to requests to determine if the issue was fixed or request for service ticket to know what had been done. GM Financial claimed dealership told them it “was just a part under warranty” well the warranty came from the replacement engine that was under the…”