2020 GMC Yukon engine problems

Filed Aug 27, 2026 · Engine · MN

Engine failure due main bearing and rod failure. Engine had heavy knocking.

Filed Aug 23, 2026 · Engine · IN

We just purchased our Yukon from a dealership in February (2/7/26) and it was diagnosed with premature failure of at least one AFM valve lifter as it is causing engine misfires, shaking and stalling on 7/30/26. We just hit 67,000 miles on the odometer so we are just beyond the warranty coverage. The lifters were replaced previously by the previous owners on 12/16/24.

Filed May 12, 2026 · Engine · CA

I took my vehicle to a dealer to repair something unrelated to the engine. They said the oil pan was leaking and pulled the pan to discover the crank shaft bearings were failing. The vehicle has 53,765 miles at this point. This appears to be the same defect being recalled on the 2022 through 2024 models.

Filed Mar 17, 2026 · Engine, Transmission · TX

The 2020 Yukon started to have serious loss of speed and decelerating issue when the vehicle would slow down and down shift to a lower gear. The issue with this is that once it downshifted it woul not engage in a gear again and leave me stranded on the road. I had to turn off the car and restart it for it to reengage in a gear enough to get it moving again and sometimes I had to try more than once to get it moving once it no longer wanted to engage in a gear. So in the 10 mile drive, I was left stranded at least 15 times. Each time I had to restart and restart again for the vehicle to engage in a lower gear. Once moving, it would sometimes it would engage in a higher gear and sometimes it would not. Thank goodness I wasn't traveling on the highway when this happened. Beware to anyone if this was to happen on the highway while in the middle lane while in traffic. And the check engine light never turned on and thus no code to help detect the issue. Took it the day before to have it looked at and was told nothing was wrong with it since there was a code and they could not duplicate the issue I described. WHAT?? They reset some transmission computer setting but it only made it worse by the next day. Now this 6 yr on 2020 GM Yukon is at the dealership service department requiring a new transmission for $7200. Said that the transmission fluid was showing particles of stuff and color was 'burnt', I think. Transmission fluid was changed at it's regular check up time so that didn't cause the issue and nor should it have bits and pieces in it and discolored. Is there any recourse to GM and it's crappy transmissions??

Filed Mar 6, 2026 · Engine · TX

TRANSMISSIONS ISSUES. Not transitioning/ shifting into gears smoothly or at all. When it does transition/shift it is rough and harsh. When my car transitions to a lower gear then it will not transition back up to a higher gear causing my vehicle to drop speed significantly that I am a safety hazard on the road. Example: when it shifts to a gear high enough that the vehicle can reach 40 mph and there is a need to decelerate it does but once it drop to lower gears it cannot engage again to a higher gear leaving me stuck going at most 10 mph with not opportunity to excelerate in traffic to a higher speed. The transmission control module (TCM) software was updated with no improvement.

Filed Feb 4, 2026 · Engine · AZ

MISFIRE ON #6 CYLINDER. DIAGNOSIS REVEALED THE INTAKE VALVE IS NOT OPENING DUE TO COLLAPSED VALVE LIFTER. No message prior to engine light coming on and car shaking after driving back from the store (speed less than 45 MPH).

Filed Jan 28, 2026 · Engine · OH

I purchased my 2020 Yukon Denali on July 8, 2024 from Classic Buick GMC in Painesville, Ohio. The check engine light started going on and off a few months after purchasing the vehicle. When I called a mechanic he stated that I should wait until the light is on and then bring in the vehicle. In early May 2025, I took my vehicle to Mike’s Automotive in Middlefield, Ohio after the check engine light began coming on during extended drives (approximately five hours or more). The shop ran a diagnostic scan and advised that the oil pump needed to be replaced. Seeking another opinion, on May 14, 2025, I brought my vehicle to Classic Buick GMC Service, the dealership where I purchased my GMC Yukon. After diagnosing the vehicle, they advised that the check engine light was related to an Engine Oil Pressure Control Solenoid stuck in the off position (P06DD). This fix would cost $3,584. This fix would require the oil pump to be replaced as indicated by the previous repair shop. On May 29, 2025, I took the vehicle to Avenue Auto Clinic in Painesville, OH, where the oil pressure valve and sensors were replaced. The mechanic also advised that I change the oil every 3,000 miles, use OEM oil filters, and thicker oil. He also advised me to check the oil every 1,000 oil and add as needed. I do have to add oil approximately every 1,500 miles and I change the oil every 3,000 miles. I am concerned that my vehicle has the same engine-related defect as the Yukon engines currently under recall. Multiple mechanics have informed me that my vehicle is equipped with the same engine as those affected by the recall. I am requesting that my vehicle be added to the recall. Yes, my vehicle is available for inspection.

Filed Jan 8, 2026 · Engine · 52,000 miles · OH

The contact owns a 2020 GMC Yukon. The contact stated that while driving at an undisclosed speed, the check engine warning light was illuminated. The vehicle was taken to the residence, the contact exited the vehicle and discovered white smoke coming from the exhaust and started to smell coolant and then discovered that the coolant level was low. The contact added coolant, and the check engine warning light was no longer illuminated. The contact’s husband and son, who were knowledgeable about vehicles, had self-diagnosed the vehicle and determined that the head gasket or the lifters might need to be replaced. The contact stated that the failure had occurred on several occasions and the contact consistently added coolant; however, the check engine warning light was illuminated every 300 miles once again. The contact researched and was made aware of an unknown the federal safety agency Campaign Number; however, the VIN was not included. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that there was an unknown internal issue with the engine that was possibly associated with coolant leaking into the engine. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 52,000.

Filed Nov 25, 2025 · Engine · DE

I purchased a new 2020 GMC Yukon in May of 2020. Between May 2020 and November 2025 the vehicle was routinely serviced on or before the due date recommend by the manufacturer. I had not experienced issues with the vehicle until November 2020 when the check engine light abruptly appeared and the vehicle began driving very rough. I immediately took the vehicle to the local mechanic who identified two codes (P0300 and P050D) related to the engine issues. The vehicle was towed to the dealership due to the fact that I was instructed it was unsafe to drive long distances without additional diagnostics. The dealership disassembled the engine and found coolant leaking into cylinder six. There were no cracks or otherwise clear means of entry for the coolant into the engine. The dealership instructed us that we would need a complete engine replacement. Upon further research of this issue, it was uncovered that a Service Bulletin had been issued for this very issue. The reference number is 20-NA-166, updated March 2024.

Filed Nov 18, 2025 · Engine · FL

total engine failure with 90,000 miles on the car.