2020 GMC SIERRA 1500 Complaints

The engine failed and started burning oil at a rate of 3 quarts every two weeks. The vehicle is currently at the GMC dealership having the engine rebuilt at a cost of over $15,000. The vehicle has approx. 116,000 miles at time of failure, so it is outside of the manufacturers warranty. The GMC dealership (Fred Anderson Greer) has photos. The engine is a 6.2L but not currently under recall as it is a 2020, the recall includes 2021 - 2024 models.

My 2020 GMC Sierra 1500 Denali with the 6.2L L87 V8 just began experiencing a new rough idle with intermittent RPM dips. There are no engine codes or warning lights. Idle drops are noticeable, suddenly began this week. I am concerned due to ongoing NHTSA Engineering Analysis EA25-007 involving this engine. Some owners reported engine failure with little warning. The truck has right over 68,000 miles on it and has had every oil changed performed at a GM dealer. I have had to top off the oil between cycles and always used the recommended oil, being the Dexos Gen 3 due to the truck burning a small amount of oil. More detail on a possible cause. I believe it would be worth investigating the DFM technology. I will be performing a fuel cleaner and possibly a lifter cleaner and/or additive. I would like to tune the truck and turn off the DFM since this is what I have read causes the truck to burn oil and damage the lifters. However, I will wait until this Analysis is completed before deciding to change the truck's stock tunes.

My engine is currently being torn down at the dealership.I heard a ticking noise coming from my engine so I took to the dealership I bought it from and when they did their diagnostics and inspection they said it was a connecting rod bearing failure.

This is the 3rd catastrophic engine failure since purchasing this new vehicle from the dealership, the vehicle is currently at the dealership and is available for inspection. The latest diagnostic report has been attached from the dealership for reference. My safety and the safety of others was at risk with each occurrence. The 1st occurred on the interstate when a lifter rod bent causing loss of power with no warning, engine was rebuilt by the dealership. The 2nd occurred on the interstate when a different lifter rod bent causing loss of power with no warning, engine was rebuilt again by the dealership. The 3rd occurred just recently while on a highway. The engine suddenly turned off with no warning. The dash told me to put it into neutral and start again. I had to coast the truck for a long distance after the sudden loss of power in order to attempt to restart the engine. The engine would not start. The diagnostic report from the dealership states "engine is seized tight, maxi fuse is blown, needs engine replacement."

First my torque converter went out, no warning lights only shaking wehn shifting, I got it replaced already it cost me $2400 Second Warning light service for Brakes, Traction and power steering come on and off. And sometimes truck doesn't brake well and steering wheel feels hard to drive, it has happened while on expressway with family. Third Engine oil low Add oil warning sign comes up alot and I have to add oil, engine has a rough idle now, also when I turn truck on smoke comes out while having a rough idle, recently it started knocking, I haven't moved the truck since than

This is a report on an incident that happened a year ago. Vehicle was taken to GMC dealer who replaced the engine at our expense. Seems to be consistent with the problem on newer GMC's that have been covered by a recall. This 2020 is one of three GMC's owned by our company. This expense was in the $12,000 range. (The 2019 experienced similar issues in 2022 and the expense was $2800 ish, and in 2024 another $1200 ish. ) Dash lit up like a Christmas tree, all warning lights on. Stalled, barely moved.

1. The vehicle’s emissions system is malfunctioning, specifically the ECM (Engine Control Module) related to the exhaust emissions system. The diagnostic trouble code is P2C7A, indicating the system is not performing as expected. Key components such as the NOx catalytic converters and diesel particulate filter have been repeatedly replaced, but the issue persists. The vehicle and all replaced components are available for inspection upon request. 2. The malfunctioning emissions system has led to an exhaust leak that allowed exhaust gases to enter the vehicle’s cab. This creates a hazardous environment for both the driver and passengers, exposing them to harmful exhaust fumes. In addition to reduced engine performance, poorer fuel economy, and emissions non-compliance, this exhaust leak poses a serious safety risk by compromising the air quality inside the vehicle. Prolonged operation under these conditions could lead to adverse health effects and further mechanical failures that impact vehicle safety. 3. Yes. The dealership has diagnosed the problem multiple times. The emissions components have been replaced under warranty on two separate occasions. The dealer attributed the fault to fuel quality; however, Fuel distributor debunked these claims. 4. The vehicle has been inspected extensively by the dealership with invoiced repair work replacing key emissions control components. 5. The check engine light and Service Engine Soon (SES) light have been illuminated with the diagnostic code P2C7A since the initial identification of the problem which started 3JUN24

Engine ticking especially when cold, dealership claims they fixed it while it was under warranty but it has continued to do it.

At approximately 54,000 miles had a complete engine failure. Lifter blew apart and damaged crank shaft. Complete engine rebuild. Rebuilt in approximately 3 weeks. 2022 At approximately 138,000 miles had another complete engine failure. Lifter blew apart again, Entire engine was replaced. New engine took 10 weeks to get. Installed in 2 days after recieved. 2025 No symptoms or warning lights present prior to failure.

While driving at highway speed and attempting to pass another vehicle, I experienced an engine failure; loss of power, noise from engine, and numerous warning messages on the display. At the GM dealer, I was informed that a pushrod (cylinder #2) was bent, the source of the engine noise. Upon further inspection (removal of cylinder heads), it was determined that the cam shaft chrome had begun to flake causing pitting (lobe damage) which in turn caused the pushrod to fail. Had the pushrod broke instead of bent at highway speed, I feel there would have been a catastrophic failure with more severe consequences for my vehicle and others around me. Vehicle was diagnosed and repaired by a certified GM dealer. There were no prior warnings/indications of problem(s). I understand there is a current recall of the GM 6.2L L87 engine for model years 2021-2024. This incident occurred on a model year 2020 GM 6.2L L87, but the issues I experienced are identical to the 2021-2024 engines identified in the recall.