Tick sound coming from underneath. Also fumes smell. Dealership found it to be the exhaust system. Said the muffler valve is bad. Quoted me $2000 for repair. Never heard of a exhaust system failure in only 5 years. Very unsatisfied with this.
2020 GMC Sierra 1500 engine complaints
Page 6 of 10: complaints 131 to 160 of 260, newest first, as owners wrote them.
I heard a ticking noise coming from the engine compartment. I took it to the dealership that I purchased the truck from and that have been using consistently for service. I was told that the noise was coming from a lifter on the driver's side of the engine and, on further investigation, it was determined that the camshaft had been damaged. I was told that it could seize up as I was driving and that my safety and those with and around me would be at risk. At 85,000 miles, the engine had failed and would have to be replaced. There was no prior warning or no check engine light and the vehicle has been in for oil changes and all maintenance at the dealership. The new engine cost me $15000 including diagnosis and towing.
I noticed a ticking sound in my 2020 GMC Sierra 1500 SLT 5.3 Liter on 10/15/2025 after it was serviced at an Authorize Buick GMC Dealership on 10/13/2025. I made an appointment and returned the vehicle to the dealership for further inspection on 10/17/2025. I was informed later that day that my truck has lifters and camshaft failure. If my truck had stalled or stopped on the express way, myself and others safety could have been at risk. My truck has only been looked at by the dealership at this time, and it is available for inspection upon request. There were no warning lights, check engine lights, messages or symptoms prior to the failure. I did get a low oil level message in April 2024 when the dealership stated they must not have put the correct amount of oil in my truck during an oil change on 1/29/2024. They inspected my truck and assured me there was no damage done to my Engine from this issue. I have recently learned there is a recall for GM Vehicles manufactured between 2021 and 2024 with the 6.2L engine installed. I am not sure why this recall does not include 2020 trucks with the 5.3L engines installed. Apparently, the same problems exist with these engines also. I received an estimate for repair approximately $13,000 which can increase once the engine is town down and inspected further. Any assistance you can provide would be greatly appreciated.
The engine failed completely while driving. On the day of the incident, I started my 2020 GMC Sierra 1500 AT4, and immediately upon cranking, the engine began knocking loudly. I shut the vehicle off right away to prevent further damage and called a wrecker service to have it towed to Marianna Chevrolet, GMC. No warning lights or messages prior to the incident. The weather was clear and dry, and the truck was parked on level ground at the time. There were no prior warning lights, leaks, or unusual noises before this event. The vehicle has been well-maintained, with oil changes performed regularly every 4,000 miles at a local auto shop (though receipts are not available). The brakes were replaced earlier in 2025. Marianna Chevrolet, GMC inspected the vehicle and estimated the repair cost at $12,700 due to what appears to be a major internal engine failure.
43000 miles 2020 gmc sierra with lifter engine issues. Oil change made every 3k miles
6.2L V8 engine in 2020 GMC Sierra 1500 AT4 suffered two lifter failures, which damaged crankshaft and sent metal shards throughout engine and oil. Total engine replacement required. This issue is subject to a recall for 2021 - 2024 model years and the recall should extend to 2020 model years. Vehicle was traded without functioning engine at a significant loss in value for new vehicle, and is not available for inspection. Vehicle was inspected by service department at GMC dealership and traded to a different GMC dealer. No prior indications of problems or warning lights until engine failure occurred while driving.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at approximately 35-40 MPH and hauling a trailer in stop-and-go traffic, there was white smoke coming from the exhaust pipe, and the vehicle started losing power. The contact was able to pull over to the side of the road, where the Electronic Stability Control (ESC) and the check engine warning lights illuminated. The parking brake was engaging and disengaging independently. After turning off the vehicle and waiting for approximately 15-20 minutes, the vehicle was restarted, and the contact drove to the nearest independent mechanic. The mechanic diagnosed the vehicle and determined that the ignition coils needed to be replaced. The vehicle was repaired; however, it was determined that the repair had not resolved the failure. The mechanic then diagnosed the vehicle's cylinder #4 failure. The mechanic was in the process of determining whether the lifter or camshaft had failed. The mechanic determined that the engine might need to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 93,000.
Engine misfiring and rough idle with occasional flashing engine light. Dealer said no codes to know what to look for despite replicating issue. Eventually it threw a Cylinder 5 misfire and thus GM dealer was able to look further. They found metal in oil pan and concluded a bearing issue and would need to replace engine.
Constant engine issues, cams, lifters. Transmission problems. These engines in these vehicles need to be RECALLED. I have bought 6 of these trucks and all of them have the same issues. SPENDING 14k on new engines one after another is ridiculous. These are classified as âworkâ trucks and canât handle âworkingâÂ
Constant engine issues, cams, lifters. Transmission problems. These engines in these vehicles need to be RECALLED. I have bought 6 of these trucks and all of them have the same issues. SPENDING 14k on new engines one after another is ridiculous. These are classified as “work” trucks and can’t handle “working“.
Constant engine issues, cams, lifters. Transmission problems. These engines in these vehicles need to be RECALLED. I have bought 6 of these trucks and all of them have the same issues. SPENDING 14k on new engines one after another is ridiculous. These are classified as “work” trucks and can’t handle “working”
Engine timing chains failed at 71,000 miles requiring a $9,700 repair. Warranty covers 5 yr/ 100k miles and was not fully covered by GM since the vehicle was 9 months beyond 5 years, yet still well within the 100k miles. Issue was diagnosed via P0016-00 being set indicating misalignment between crankshaft position sensor and the intake camshaft position sensor. This issue is a known problem with the early LM2 engines, and the timing chain was upgraded in later LM2 engines. Early adopters of the LM2 are left to pay the price for a defective part.
The engine coolant control valve on my 2020 GMC Sierra 1500 with the LM2 Duramax diesel failed. The failed part is still in my truck, which remains at the dealership awaiting replacement. The repair is delayed due to the part being on nationwide backorder, further highlighting that this is a widespread issue. When the valve failed, the truck entered reduced engine power mode while I was traveling on the interstate. This limited my speed to about 40 mph while climbing a hill. The sudden loss of power in high-speed traffic created a serious safety hazard, as it significantly increased my risk of being rear-ended or involved in a collision with faster-moving vehicles. I drove the truck directly to the dealership after the incident, where the problem was immediately confirmed. The issue was diagnosed and confirmed by the dealership, which identified the coolant control valve as the failed component. To my knowledge, GM has not yet inspected this specific failure. Prior to the loss of power, the truck displayed a “Reduced Engine Power” warning message and the check engine light on the dashboard. These warnings appeared at the time of the failure. Importantly, GM has already acknowledged this issue by issuing Special Coverage N252508341 for 2021 and 2022 GMC Sierra 1500 trucks with the same LM2 engine and the same coolant control valve part numbers. However, the 2020 models (like mine) were excluded from that program despite using the identical part and engine configuration.
2020 gmc sierra 1500 elevation 5.3l engine. Lifter failure due do faulty design I’m afm/dfm systems.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle jerked abnormally while depressing the accelerator pedal. A dealer was contacted. The vehicle was taken to the dealer, and the technician informed the contact that the failure might be related to the engine or transmission; however, the contact was informed that the vehicle needed to be inspected to determine the cause of the failure. The vehicle was not repaired. The contact stated that the failure had occurred several times. The manufacturer was notified of the failure and informed the contact to file a complaint with the federal safety agency Hotline. The approximate failure mileage was 41,248.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 40 MPH, there was an abnormal knocking sound coming from the engine compartment. The contact stated that several unknown warning lights were illuminated, and several messages were displayed. The vehicle was driven to the side of the road to safety and turned off. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The failure milage was approximately 76,000.
The contact owns a 2020 GMC Sierra 1500. The contact stated that on several occasions while the vehicle was started, the check engine, brake system, and another unknown warning light illuminated. Additionally, the messages brake system failure, steering wheel failure, low oil, and two other unknown messages were displayed. The contact also stated that the rear-view camera remained displayed while shifted into drive, and the instrument panel failed to operate as intended. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 65,000.
Vehicle: 2020 GMC Sierra Denali 1500 (VIN: [XXX] ) Description of the Problem: My 2020 GMC Sierra Denali has developed serious engine problems that create unsafe driving conditions. On [XXX], I documented loud knocking and clicking noises coming from the engine. The vehicle also shows warning lights and unpredictable performance. Because of these defects: •I cannot safely drive the truck without risk of engine failure while on the road. •The noises and mechanical issues raise concerns about potential loss of power, stalling, or catastrophic engine damage at highway speeds. •No independent mechanic will touch the vehicle because of the complexity and risk of the defect, leaving me stranded. General Motors has refused to take responsibility, and the BBB AUTO LINE denied my case due to mileage, but the defect itself is unrelated to mileage or normal wear. This is a manufacturer defect that creates a safety hazard for me, my family, and other drivers on the road. What I’m Requesting: I am asking the federal safety agency to investigate this issue with GMC Sierra models, as these engine defects make the vehicle unsafe to operate and could lead to accidents if the engine fails while driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
My 6.3l v8 Started having a slight misfire while driving. Took vehicle to a mechanic and was advised to change the spark plugs, changed spark plugs, spark plug wires, and ignition coil packs while still experiencing sudden misfires while driving. Starting to consider the 6.2L L87 collapsing cylinder issue.
I have a 2020 sierra 1500 6.2 with 86,000 miles. I have only had this truck 6 months. This was inspected before I purchased with no engine issues. Since purchasing we have driven less than 6000 miles. While driving my vehicle the rod in the engine failed and started knocking. I am a mechanic and I am GMC master certified. Both myself and the owner of the shop I work at diagnosed the vehicle with a bad engine. We looked at the recall for the 6.2 engine and noticed that many of the 2020 vehicles with this engine have the same issue that is currently being recalled for this specific engine. I called GMC and they won’t fix the issue that the vehicle is having. They won’t perform the recall and again I have only had this vehicle for 6 months and with 86,000 miles should not be having this issue. I am GMC certified and told them that I looked into the recall and they them selves state that some of the defective engines got out into the 2020 models.
For approximately the last year (2024-2025) my 2020 GMC Sierra 1500 AT4 with the 6.2L engine has had noticeable ticking, knocking, and unprovoked shaking upon start up and idle. The pickup has stalled out at stop lights and intersections in the past, posing risk. In June (2025) the pickup was taken to a certified mechanic for inspection who suggested possible lifter or valve failure. The vehicle exhibits a persistent ticking sound from the engine, which I believe may be related to lifter or valve issues, similar to those reported in lawsuits against GM for 2019-2024 models and the recall for 2021-2024 models (the federal safety agency Recall ID: 24V‑676). This ticking occurs regularly, including at approximately 54,500 miles, and raises concerns about potential engine failure or sudden loss of propulsion, which could be hazardous, especially at highway speeds. I have noticed approximately 2 quarts of engine oil usage per my last 2 oil changes (roughly every 6,000 miles). I recently had taken the pickup to a local GM dealership where they informed me that I am not longer covered under warranty and the recent recall is not applicable. I was advised to “keep and eye on it, and get a AAA membership”. I am aware of at least 10 class action lawsuits against GM for similar engine issues in vehicles like mine, suggesting a widespread defect. These issues, combined with the potential for engine failure or impaired vehicle control, warrant investigation to ensure driver safety. I have records of the ticking sound and can provide further details if needed. I am willing to cooperate with the federal safety agency for inspections or further documentation.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving with cruise control mode set at 55 MPH, the vehicle independently accelerated to 98 MPH, and then the vehicle lost motive power. Additionally, the contact stated that the vehicle had failed to turn off upon pressing the Engine Start/Stop button. No warning light was illuminated. The vehicle was able to restart and was taken to a local dealer to be diagnosed, but the cause of the failure could not be determined. Additionally, the contact noticed that water was leaking inside the vehicle through the rear window on rainy days. The contact stated that the infotainment screen had failed to turn on as intended on some occasions, and the screen had displayed a rearview camera image while the vehicle was in drive(D) on other occasions. The contact stated that while driving at various speeds, the transmission made an abnormal sound, and the RPMs failed to decrease as intended, but suddenly dropped while decelerating. Additionally, the contact stated that the headlights, the fuel pump, and the main pulley were replaced at the local dealer. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the federal safety agency Hotline for assistance. The failure mileage was approximately 250.
My GMC had a terminal engine failure around 5/3/25. This disengaged the ESC, parking brake, and driver assist abilities as well as making the truck undrivable. GMC service diagnosed the truck needed an entire new engine. The repair took over 2 months to complete and now that I have the truck back, the adaptive cruise control is not working.
Check engine light came on. Cooling fan for engine running none stop. Reduce power mode from engine. Took to dealer, said it’s the coolant control valve. Dealer said the part is on back order and don’t know when they will get it in. Looked up the issues and sounds like many people are having the same problem with the 3L diesel from GMC. These people reporting the same thing and having to wait months for the part. My truck was just out of warranty by 200-300 miles
On June 19th, 2025, I was driving to work when my truck began to lose power, and the check engine light came on. The error on the display is Loss of Engine Power. I took it immediately to Oreilly's so they could run the free engine light check. When they got the report, the employee was amazed that there were over 45 problem codes showing up. As I drive the vehicle there is a pull back from the engine before it starts to pick up speed. On braking as well there is a little kickback before it comes to stop. It takes more foot pressure to pick up speed. The Truck using up more fuel because of this issue. I took the truck to a local certified mechanic, and he ran the diagnostics as well and it came up with the over 45 problem codes as well. His recommendation unfortunately was to take into the dealership so they could check it and see if they have a solution for this engine malfunction and error codes.
Engine overheating at 50,000 miles. Temp would intermittently jump up to 230plus degrees while driving. Radiator replaced per dealership diagnosis. Issue still happening.
Woke up one morning and the entire back seat, entire truck flooring was soaking wet. Got it to Gerber collision in El Reno, Oklahoma. They said that the back window had a crack in it. My insurance said it is a mechanical issue on the sliding back glass and they do not cover such issue. Also want to turn in that the transmission in this truck had to be replaced two week prior to this incident. The truck only had 118,000 miles on it. Safe to say that this 10 point GMC diesel truck is a nightmare and the entire truck is a hazard. They need to take these truck off the market.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving on a main road at 40 MPH, the vehicle lost automotive power, causing the vehicle to shut off. There was no warning light illuminated. The vehicle was towed to a local dealer where the vehicle was diagnosed, and the contact was informed that the engine wiring harness was faulty and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 80,000.
The contact owns a 2020 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, there was an abnormal knocking sound coming from the engine compartment before the vehicle lost motive power with the check engine warning light illuminated. The vehicle was towed to the residence. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The dealer referred the contact to the manufacturer for further assistance. The manufacturer was made aware of the failure. The approximate failure mileage was 138,000.
I own a 2020 GMC Sierra 1500 with a 5.3 liter engine..... My engine lifters failed at 105,235 miles.... Lifter broke and damaged the Cam Shaft to a point that required full engine replacement costing me $10,800. When I asked GM for help, they denied because I went to a local repair shop with certified mechanics. I believe GM is fully aware of this problem and they are ignoring I think GM should pay for at least half of my repair bill. Thank you!
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