Diagsheet

2021 GMC Sierra 1500 · symptom sheet

Engine overheats or leaks coolant

  • 50owner reports
  • 98,500median miles
  • $499median quote
  • 0involved a crash

Newest report Sep 8, 2026 · checked Sep 19, 2026

337 of the 553 complaints on this car are about the engine. 50 of those describe overheating.

Tick what matches of 50 reports

7
46
5
1
1

What got replaced

Owners who name the part that was replaced mention the radiator (4 reports) and the coolant hose or reservoir (3 reports).

Recalls and investigations

One recall on the engine covers the 2021 model year. A recall on the same system isn't always the same failure, so read the defect text.

25V-274Apr 24, 2025
Engine And Engine Cooling:Engine:Hard Parts Internal/Mechanical

General Motors LLC (GM) is recalling certain 2021-2024 Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban, and Tahoe, GMC Sierra 1500, Yukon, and Yukon XL vehicles equipped with a 6.2L V8 gas engine. The connecting rod and/or crankshaft engine components may have manufacturing defects that can lead to engine damage and engine failure.

Risk and remedy
Risk: Engine failure increases the risk of a crash.
Remedy: Dealers will inspect the engine, and as necessary, repair or replace the engine. For vehicles that pass inspection, dealers will add higher viscosity oil, install 6 oil fill cap, replace the oil filter, and update the owner's manual. Repairs will be performed free of charge. Owner notification letters were mailed June 18, 2025. Owners may contact Cadillac customer service at 1-800-333-4223, Chevrolet customer service at 1-800-222-1020, or GMC customer service at 1-800-462-8782. GM's number for this recall is N252494000.

NHTSA investigations into the engine on the Sierra 1500

EA26-005opened Aug 20, 2026
Engine · model years 2021 to 2026

Loss of motive power due to engine failure post recall remedy. Open.

NHTSA summary
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 c
RQ26-001opened Jan 16, 2026
Engine · model years 2021 to 2024

Loss of motive power due to engine failure post recall remedy. Closed aug 20, 2026.

NHTSA summary
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.
EA25-007opened Oct 23, 2025
Engine And Engine Cooling · model years 2019 to 2024

Loss of motive power due to engine failure. Open.

NHTSA summary
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.
PE25-001opened Jan 16, 2025
Engine And Engine Cooling · model years 2019 to 2024

Loss of motive power due to engine failure. Closed oct 23, 2025, led to recall 25V-274.

NHTSA summary
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

What owners paid

12 of the 50 reports quote a price. Each dot is one quote. The middle half runs $395 to $2,400.

$395$499$2,400
$0k$2k$4k$6k$8k

When it happens

The middle half of failures fell between 50,000 and 122,691 miles, from the 12 reports that gave a mileage.

121
122
324
2325
2226

What owners wrote

“I have a 2021 GMC Sierra 1500 AT4 3.0L diesel pickup truck with 98,500 miles. The coolant control valve failed on my vehicle and for some reason it is not covered under GM's special bulletin that covers this part 15yr/150,000. Ridiculous.”

Filed Apr 8, 2026 · 98,500 miles

“I had an engine warning warning light on my dash around May 5th. A notice of reduced speed also lit up my dash while I was on the freeway. I scheduled a service for May 15th and was told the engine coolant flow control valve needed to be replaced. I was also told there was a backlog of other vehicles waiting for the same part. It has been over a month and I am still unable to drive my truck which I use for work.”

Filed Jun 17, 2025

“The truck ever since of bought it has been nothing but issues. Starting with the fuel pump issues then electrical issues and most recently the coolant flow control valve. This is my work truck and now I’m out of a truck with no loaner and the dealership has no eta.”

Filed May 29, 2025

“code P1098. Engine light comes on, power is reduced, coolant fan runs on high. Temp gauge fluctuates. This last for 20 minutes or so. The engine then returns to normal. After a few days the engine trouble light goes off. This happens every several weeks. Parts are backlogged and I understand this is a common problem with this engine. I have 64000 on it.”

Filed May 19, 2025

Should you keep driving it?

This page can't tell you that. 0 of 50 reports involved a crash. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.

File your own report with NHTSA. Complaint counts are how a problem gets an investigation.

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