2021 GMC Sierra 1500

On January 16, 2026, the Office of Defects Investigation (ODI) opened Recall Query RQ26001.  This investigation was opened to assess the remedy effectiveness of Recall 25V-274. ODI has received complaints alleging engine failure in vehicles after the recall remedy had been completed, whether that remedy involved an oil viscosity change or a complete engine replacement. General Motors (GM) issued Recall 25V-274 to address concerns of engine failure in the L87 engines produced between March 1, 2021 and May 31, 2024. GM cited the root cause as a supplier manufacturing and quality issue. GM’s recall remedy for Recall 25V-274 consisted of two different repairs, either an oil viscosity change or an engine replacement, based on the results of the remedy inspection procedure. ODI continues to receive reports of engine failures after the completion of the recall remedy. To date, ODI has received 499 complaints alleging post-remedy engine failure in vehicles subject to Recall 25V-274, 473 of which involved an oil viscosity change and 26 a complete engine replacement. Additionally, ODI has received 191 reports of L87 engine failures in engines produced after the production period cited in Recall 25V-274. GM reported receiving 6,953 complaints of post-remedy engine failure. ODI is opening this Engineering Analysisto continue investigating complaints of post-remedy engine failure. ODI is expanding the scope of this Investigation to include engines produced after the production period cited in the recall. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

The Office of Defects Investigation (ODI) has received 1,157 reports of engine bearing failure failures in the L87 6.2L engine produced by General Motors (GM). Of the 1,157 reports received, 173 are outside of the scope of recall 25V-274. These engines are installed in Model Years (MY) 2019–2024 Chevrolet Silverado 1500 and GMC Sierra 1500, and 2021-2024MY Chevrolet Suburban and Tahoe, GMC Yukon/Yukon XL, and Cadillac Escalade/Escalade ESV vehicles. The subject engine failures were investigated as part of a Preliminary Evaluation (PE25001).  GM determined that these engine failures were due to multiple supplier manufacturing and quality issues. GM issued recall 25V-274 to address the supplier manufacturing and quality issues produced between March 1, 2021, and May 31, 2024. Based on the issuance of recall 25V-274, NHTSA has closed PE25001. ODI continues to receive a significant number of reports of engine failure in vehicles outside the scope of 25V-274.  This presents a potential safety risk that warrants further investigation.  ODI is opening this Engineering Analysis (EA) to further evaluate the scope and severity of the potential problem and to fully assess the potential safety-related issues of vehicles built outside the recall scope. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

On January 16, 2026, the Office of Defects Investigation (ODI) opened Recall Query RQ26001.  This investigation was opened to assess the remedy effectiveness of Recall 25V-274. ODI has received complaints alleging engine failure in vehicles after the recall remedy had been completed, whether that remedy involved an oil viscosity change or a complete engine replacement. General Motors (GM) issued Recall 25V-274 to address concerns of engine failure in the L87 engines produced between March 1, 2021 and May 31, 2024. GM cited the root cause as a supplier manufacturing and quality issue. GM’s recall remedy for Recall 25V-274 consisted of two different repairs, either an oil viscosity change or an engine replacement, based on the results of the remedy inspection procedure. ODI continues to receive reports of engine failures after the completion of the recall remedy. To date, ODI has received 499 complaints alleging post-remedy engine failure in vehicles subject to Recall 25V-274, 473 of which involved an oil viscosity change and 26 a complete engine replacement. GM reported receiving 6,953 complaints of post-remedy engine failure. ODI will close this RQ and continue to investigate complaints of post-remedy engine failure for Recall 25V-274 as part of an Engineering Analysis (EA26005). To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

On January 16, 2025, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE25001 after receiving complaints and field reports concerning engine failures in MY2019-2024 GM’s full-size truck and SUV T1XX platform equipped with the L87 6.2L V8 engine. These complainants alleged engine bearing failures resulting in knocking and growling noises from the engine’s bottom end and in some cases more severe consequences such as broken connecting rods leading to engine damage, or engine failure. If the engine fails during vehicle operation, the vehicle will lose propulsion, increasing the risk of a crash. On April 24, 2025, GM issued recall 25V-274 to address the concern with L87 engines produced between March 1, 2021, and May 31, 2024.  GM cited the root cause as a supplier manufacturing and quality issues. GM’s  recall remedy will be either an oil change to an oil with a different viscosity or engine replacement depending on the results of the remedy inspection procedure. To date, ODI has received 1,157 allegations of engine bearing failure. GM submitted 55,464 reports in total, with 29,752 unique VINs. ODI continues to receive allegations of L87 engine failures which fall outside of the scope of recall 25V-274. Based on GM’s recall, ODI will close this PE. NHTSA will continue to investigate complaints of engine failure outside the scope of recall 25V-274 as part ofEngineering Analysis (EA25007). To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

GM has a known issue with coolant control valves that can cause vehicles to go into reduced power mode creating drive-ability and safety concerns in busy traffic situations. They have issued a TSB (N252508341) for certain VIN numbers but have ignored similar issues in other VINs.

NHTSA ID

11775708

Incident

Oct 30, 2026

The contact owns a 2021 GMC Sierra 1500. The contact stated that while attempting to start the vehicle, the engine failed to turnover. The vehicle was towed to the residence. The contact stated that the vehicle was inspected and it was determined that the engine had seized. The engine was rebuilt and the vehicle was repaired. The manufacturer was notified of the failure. The contact associated the failure with NHTSA Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING). The failure mileage was 142,767.

NHTSA ID

11774746

Incident

May 10, 2026

Mileage

142,767 mi

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 45 MPH, there was an abnormal knocking sound coming from the vehicle. The vehicle started hesitating, and there was a loss of power that became worse over time. Additionally, the “Service Engine” and “Power Train” warning lights were illuminated. The messages “Loss of Steering Assist - Be Alert” and “Service Parking Brake” were displayed. The following day, the vehicle was driven in LIMP Mode to the dealer and was diagnosed with engine failure. The contact stated that there was an ongoing NHTSA investigation associated with the 6.2L engines. The failure mileage was approximately 34,000.

NHTSA ID

11774637

Incident

Oct 28, 2026

Mileage

34,000 mi

This truck has the 6.2L power train and the engine failed and needed to be replaced at approximately 70,000 miles. After replacement around 80,000 miles I then needed to have the water pump replaced because it failed as well.

NHTSA ID

11774585

Incident

Nov 20, 2025

I have repeatedly experienced a noticeable exhaust odor inside the cab while operating the vehicle\. The condition is particularly pronounced during cold weather when the vehicle is idling\. Under these circumstances, the exhaust smell inside the passenger compartment is distinct and concerning\. I have taken the vehicle to two separate General Motors dealerships in an effort to identify and resolve this issue\. On both occasions, I was advised that the vehicle was fine\. Despite these visits, the problem remains unresolved, and I continue to experience exhaust fumes inside the cab under the conditions described above\. My concern is that exhaust gases may be entering the passenger compartment, potentially exposing the driver and passengers to harmful emissions, including carbon monoxide\. Because carbon monoxide cannot be detected by smell, the presence of an exhaust odor does not establish whether carbon monoxide is present or at what concentration\. However, the recurring odor warrants a thorough investigation to determine its source and whether a potentially hazardous condition exists\. I am concerned that the issue may not be adequately identified during routine dealership inspections if the vehicle is not evaluated under the specific conditions in which the symptoms occur\. The fact that two dealerships have indicated that the vehicle is operating normally does not resolve my concern, particularly because the symptoms continue to occur\. I am requesting that the National Highway Traffic Safety Administration review this complaint and determine whether further investigation is warranted into the possibility of exhaust gases entering the passenger compartment of this vehicle\. I would appreciate consideration of whether this condition could represent a safety\-related defect that may affect other vehicles of the same make, model, or model year\. I have made reasonable efforts to address this matter through authorized GM service facilities.

NHTSA ID

11774349

Incident

Oct 1, 2025

I am experiencing hard gear shifting in the low gears. It is very noticeable and I have a 10-speed transmission.

NHTSA ID

11774276

Incident

Jun 11, 2026

2021 GMC 3.0 Diesel have coolant control valve issues. GM has a special coverage for them under Special Coverage N252508341. That coverage covers my year make and model. I have an open case with GM under GMC Customer Assistance opened case 116070735. GM is refusing to cover it due to this cited email. "After reviewing the vehicle information, we determined that Special Coverage N252508341 does not apply because it is not associated with the vehicle identification number (VIN) on your vehicle." I had the dealership and GMC customer service confirm this. GMC told me to request goodwill assistance at the dealership which the service provider had never heard of before. I can provide all documentation needed. I had recurring P1098, followed by a reduced engine power warning and unusually loud radiator fans. I figured it may be the coolant control valve and found Special Coverage N252508341. I created an open case with GM and took it to the dealership. The dealership was ambiguous about the issue and quoted me over 2,000 dollars just for further diagnostics citing "Coolant" and "Valve" in the documentation. They also said once they find the issue it would be "more." I took it to a 3rd party mechanic for an actual understanding of the issue. The mechanic found that the issue was the coolant control valve, which I have in documentation, and recommend a clear understanding of the repair and quote for the repair.

NHTSA ID

11774225

Incident

Oct 23, 2026

Engine locked up while driving down the road at highway speeds. Lost all power and had to pull to shoulder of road. Was towed to dealership and confirmed engine locked up and covered under special recall. Was looked at a few months back and passed the recall test on engine. No lights or signs of engine failure before failure.

NHTSA ID

11772830

Incident

Oct 18, 2026

This Preliminary Information communication provides information to the technician about vehicles that have an intermittent no crank, no start, or start stall concern with the security light coming on. Technician may find Diagnostic Trouble Codes B3055, B3

Beginning with 2026 model year production, the floor console/armrest lamp design was changed by removing the tilt-switch ball. As a result, the lamp remains illuminated when the floor console compartment lid is closed. The BCM turns the lamp off after the ignition is switched off to prevent battery rundown. This PI is to inform dealers of the change in the lamp and operation of the lamp following repairs.

This document assists GM dealer technicians with diagnosing torque converter concerns to ensure torque converter replacement is necessary. The torque converter part number will be placed on order restriction, and the technician will be asked to follow 25-NA-148 before requesting a part through PQC.

This Preliminary information communicates that it is normal for the tailgate to drop faster than it used to after the GM Accessory Kicker Audio System is installed.

• Improvements to OnStar functionality.

This document assists GM dealer technicians with diagnosing torque converter concerns to ensure torque converter replacement is necessary. The torque converter part number will be placed on order restriction, and the technician will be asked to follow 25-NA-148 before requesting a part through PQC.