MY 2020 GMC SIERRA DENALI EXPERIENCED A COMPLETE ENGINE FAILURE in June of 2024. Dealer repair was in excess of $7,700. They stated they knew this was going to happen at about the 70,000 mile mark as they have fixed many in that same time. Repair resulted in rod replacement and cam shaft damage and replacement.

- Morgantown, WV, USA

My 2020 GMC Sierra with a 5.3L engine and 78,272 miles on the vehicle, experienced damaged lifters which also resulted in a damaged cam shaft. The total repair bill was $9,208.86. While in the GMC dealership for repair, there were 2 other trucks - same model, same year, same engine - in for the same repair. When searching on-line, I found the recall for the GMC 6.2L engine for similar issues. It is my opinion that the 5.3L engine is experiencing the same types of issues. I have driven GMC trucks for almost 40 years and have never experienced these types of issues. I have been told by several people that it is related to the Dynamic Fuel Management system and to fix the problem to disable the system to keep the truck in V8 mode. There are several solutions on line to make this happen. I am no engineer and only provide this as background information. From my perspective, it is clear that GM has a problem (whatever the root cause) with their 5.3L engines.

- Fenton, MI, USA

We were driving down the interstate at about 75 mph when a message came up that said to shift to neutral and push the start button. My husband did and it continued to drive perfectly fine, but about 6 miles down the road it did the same thing again except when he pushed the start button it did not start. I cannot begin to tell you the cause as to why it would-??ve been doing that as I have never had any other issues with it.

- Palatka, FL, USA

Bought the truck less than four months ago and as of yesterday it consumed a substantial quantity of oil and later refill. However today it made a noticeable noise until it shut off permanently. Dealer did not disclose this

- Cumming, GA, USA

I started to notice changes in performance around 75k miles. Seemed like performance was subpar compared to what was the norm. Seemed to lose some power. Minimal at first, more so just recently around 90k. Oil consumption was starting to accelerate at each oil change at 75k, 80k, 85k, 90k. To the point around 85k and 90k that I would not go over even 1 mile from the 5k threshold without changing the oil. Around 90k I could tell it was not getting any better, deficiencies were accelerating it seemed. At 91k miles I started to hear clicking noises and loss of power, starts were getting rough, bouncing at idle. I stopped driving it, only driving it to the dealership where I brought for a look at it. Will be driving it again for them to do a deeper diagnostic. Many misfires at cylinder 5. PO305 the issue. Showed up around 91k miles on 12/17/25 Now investigation into my model. I see online.

- Lomira, WI, USA

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 35 MPH, the vehicle lost automotive power with the check engine warning light illuminated and the message "Vehicle Might Lose Power" displayed. The vehicle remained at the residence, and the contact used a self-diagnostic tool to retrieve a fault code related to the coolant valve D. The contact determined that the coolant valve D needed to be replaced. The vehicle was taken to an independent mechanic; however, the contact was unaware of the part that needed to be fixed in the vehicle. The vehicle was repaired. The contact researched and was made aware of an unknown NHTSA Campaign Number; however, the VIN was not under recall. The manufacturer was contacted and confirmed that the VIN was not under recall. The failure mileage was approximately 31,000.

- El Granada, CA, USA

Fuel management system caused a lifter to fail (stuck) which resulted in camshaft damage at 77,611 miles. GM refused to cover the repair, although there is a pending class action lawsuit against GM for this very issue. Truck was repaired at a GM dealership - Sunrise Collierville, TN. Repair costs was approximately $7,000. This occurred during a 2.5 hour road trip which put lives at risk. The truck began to vibrate, and the check engine light came on. There was no other warning before the failure occurred. No police or insurance were involved. This occurred on 9/27/25. It took the dealership 32 days to diagnose and repair the issue. Thanks.

- Germantown, TN, USA

The contact owned a 2020 GMC Sierra 1500. The contact stated that after the vehicle was purchased and while driving at an undisclosed speed, the check engine warning light illuminated. The dealer was contacted. However, the check engine light turned off, and the dealer refused to inspect the vehicle. The contact stated that while driving at an undisclosed speed, the vehicle jerked and the check engine light illuminated. The dealer was contacted. However, the warranty had expired, and the dealer refused to inspect the vehicle. The manufacturer was contacted, and the contact was offered a five-hundred-dollar coupon. The vehicle was taken back to the dealer. However, no cause for the failure was found. The contact stated that an unknown part was replaced. The contact stated that the failure persisted. The contact stated that while turning on the engine, the contact's sister informed him that smoke was emitting from under the hood. The contact turned off the engine, opened the hood, and noticed that all of the wires were melted. The contact splashed water on the wires. The contact checked underneath the vehicle and noticed that the plastic that was burnt was leaking residue. The vehicle was left at the residence where the contact's mother lives. The next day, the contact noticed that the front windshield had shattered due to the heat from the burnt wires. The insurance company was notified and referred the caller to take the vehicle to be inspected. The vehicle was towed to a collision center. The contact was informed that the vehicle had a factory defect. The vehicle was not repaired. The manufacturer was notified of the failure. However, no assistance was provided since the warranty had expired. ?The failure mileage was approximately 32,000.

- Fremont, CA, USA

In December of 2023 my 2020 GMC Sierra 1500 was driving down the freeway, experienced a jerking and low oil pressure. Pulled over and shut vehicle off and wouldn't turn back on, engine locked up. The vehicle received a brand new 6.2l replacement motor in April of 2024- $15k in parts and labor. This vehicle was not included in the recent recall, but obviously experienced a similar issue. This was at 75k miles. The car was owned by a different owner at the time of the engine failure. I bought the vehicle as a repo and proceeded to get the engine fixed on it.

- Washington , MI, USA

Engine lost all power while driving highway speed. Vehicle towed to Cavender Chevrolet dealer in Boerne, TX. Dealer inspected and determined cam bearings damaged. Engine replaced with remanufactured engine.

- Bulverde, TX, USA

My 2020 5.3 L GMC AT4 is experiencing loss of power with bucking & stalling. Cylinders are not activating when called check engine light is flashing, it starts rough and makes numerous noises at various speeds, as well as at idle. So I brought my vehicle to my local auto repair shop. Our mechanic found two failed fuel injectors and a failed throttle body. Then the loud knocks in my block failed an acoustic test. He also determined the lifters, push rods and camshaft are experiencing excessive wear. The afm system has failed! he warned me that further use of my motor (with only 42K miles on it) will cause a catastrophic failure. My research shows that these issues are becoming common of 5.3 GMC motors. We searched the country for a rebuilt motor and found that none are available for the next several months. However, I was able to find a new motor at much greater cost. GMC has declined assistance at this time. My vehicle has no value as is, so I ordered the new GM engine. Without the dod system, these engines were designed to go well over 100,000 miles. I am a faithful GMC owner and none of my previous GMC trucks (2003, 2013, 2015, 2019) had such a major problem. Now the 2020's fuel saving system has failed and requires repairs that amount to half the value of my truck. When a full size truck stalls on the highway it's certainly life threatening.

- Preston, CT, USA

Ticking noise coming from engine slight metallic noise as well. RPMs drop and when they drop, you can feel power loss constant hunting in the RPMs. Also a weird vibration, not all the time in the front end somewhere.

- Mount Holly , NJ, USA

Driving on the Highway, the engine shuttered, but kept going. When I had to slow down, the engine stalled and would not restart. It left me in the center lane of a three lane highway. I was able to push the vehicle off to the side of the road. Very dangerous. No warning lights came on, no alerts. I had the truck towed to Folsom Buick & GMC in Folsom CA where the diagnosed a complete engine failure. The have now had my truck for a full month. They are trying to get GMC to share the cost of the replacement motor. In the meantime, I'm renting a pickup truck so I can continue to work.

- El Dorado Hills, CA, USA

-lifter failure on 6.2 v8 engine, causing damage to camshaft -lost significant propulsion while driving on the highway, nearly avoided being rear-ended by another vehicle due to loss of vehicle propulsion -dealer had to to replace lifter bank and camshaft -no issues, once lifter failed dash lights all lit

- Fort Hood, TX, USA

Engine fan has been constantly running, with engine temp reading around 230 consistently. After driving 5 miles on the interstate it shot up to 260 and said -??engine temp overheating, idle engine-??.

- Bennett, CO, USA

I am Having direct issues with the engine when the vehicle is started and continues while idling or driving at any rate of speed.There's a continuous "Knocking" noise that has concerned me for a while now. My vehicle (2020 GMC Sierra 6.2 liter gas engine) with almost 100,000 miles has been doing this for a while now (at approximately 50,000 miles) and (was documented at the dealership when I made a complaint which included what I considered the vehicle to be using/losing more "oil consumption" than the normal 3-4 quarts between oil change) dating back to 2022 0r 2023 when I was told by the dealership that the amount of oil being used/ lost still fit within the manufacturers specifications.

- Saint Charles, MO, USA

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.

- Travelers Rest, SC, USA

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.

- Winterville, NC, USA

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.

- Little Rock, AR, USA

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."

- Sheboygan Falls, WI, USA