Recall 21V496 covers 338,020 2017-2019 Chevrolet and GMC heavy-duty trucks for engine-block-heater fire risk. Free repair at any franchised Chevrolet dealer.
Chevrolet is recalling 338,020 2017-2019 Silverado 2500, Silverado 3500, Sierra 2500, and Sierra 3500 trucks equipped with the Duramax diesel 6.6 liter engine and optional engine-block heater cord. An electrical short in the heater cable or terminals can raise the risk of a fire, and the dealer repair is free.
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What's wrong?
The engine-block heater on affected 2017-2019 Silverado 2500, Silverado 3500, Sierra 2500, and Sierra 3500 trucks helps warm the Duramax diesel 6.6 liter engine before a cold start. The power cord connects the heater to an outside electrical source, so the heater can warm the engine block while the truck is parked.
The problem starts when coolant leaks around the block-heater heating element. If that coolant reaches the heater cable terminals while the cord is plugged in, it can create an electrical short. GM traced the leak path to contamination on the sealing surface during assembly, which can keep the heater from sealing correctly.
Warning signs include smoke, a burning smell, poor heater performance, tripped circuit breakers, blown vehicle fuses, visible damage near the heater or cable, or coolant pooling under the truck. If any of those signs appear after plugging in the heater, stop using the block heater until a Chevrolet dealer checks it.
Who's affected?
Covers the 2500 and 3500 versions of the Silverado and Sierra, all involving the engine block heater.
| 2017 Chevrolet Silverado 2500 | Engine block heater |
|---|---|
| 2017 GMC Sierra 3500 | Engine block heater |
| 2018 GMC Sierra 3500 | Engine block heater |
| 2017 GMC Sierra 2500 | Engine block heater |
| 2018 GMC Sierra 2500 | Engine block heater |
| 2017 Chevrolet Silverado 3500 | Engine block heater |
| 2018 Chevrolet Silverado 2500 | Engine block heater |
| 2019 Chevrolet Silverado 2500 | Engine block heater |
| 2019 GMC Sierra 3500 | Engine block heater |
| 2019 Chevrolet Silverado 3500 | Engine block heater |
| 2018 Chevrolet Silverado 3500 | Engine block heater |
| 2019 GMC Sierra 2500 | Engine block heater |
| Units affected | 338,020 |
| Field incidents | NHTSA has logged 139 field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific pickup truck.
What's the safety risk?
An electrical short-circuit increases the risk of a fire. Warning signs include smoke, a burning smell, poor block-heater performance, tripped breakers, blown fuses, damaged heater parts, or coolant pooling under the vehicle. Stop using the block heater and schedule the recall repair. Repair is free at any franchised Chevrolet dealer.
What should I do?
- Check your VIN to confirm your 2017-2019 Chevrolet Silverado 2500, Sierra 3500, Sierra 2500, or Silverado 3500 is included in this recall.
- Contact a franchised Chevrolet dealer to schedule the free engine-block-heater and heater-cord replacement that fixes the short-circuit fire risk.
- Bring the recall notice if Chevrolet mailed one. If not, reference recall number 21V496 when you call.
- Avoid plugging in the engine-block heater until the dealer repair is complete.
- Call Chevrolet customer service at 1-800-462-8782 with questions about the repair.
What happens at the repair
At the dealer, a Chevrolet technician replaces the engine block heater and heater cord. On trucks that were handled earlier by disabling the feature, GM provides replacement block heaters and cords through a separate customer satisfaction program at no charge. For vehicles covered by the earlier heater cord repair, the cord is replaced and rerouted. The recall repair is free. GM's standard reimbursement plan covers owners who already paid for related repairs before the recall notice. Bring repair documentation to the service desk or contact GMC customer service to start the claim.
| Reimbursement | Reimbursement available |
|---|
Timeline
| July 1, 2021 | NHTSA published the recall |
|---|---|
| July 1, 2021 | Dealer notification began |
| July 1, 2021 | Dealer notification ended |
| August 16, 2021 | Interim owner notification (was planned for this date) |
| November 30, 2021 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| April 4, 2022 | Owner notification mailed |
Frequently asked questions
What is recall 21V496?
Recall 21V496 covers 338,020 2017-2019 Chevrolet Silverado 2500, Silverado 3500, GMC Sierra 2500, and Sierra 3500 trucks with a Duramax diesel 6.6 liter engine and optional engine-block heater cord. An electrical short-circuit in the heater cable or terminals can increase fire risk.
What should I do if my 2017-2019 Chevrolet Silverado 2500, Silverado 3500, GMC Sierra 2500, or Sierra 3500 is on this recall?
Check your VIN to confirm your specific truck is included in recall 21V496. If it is, contact a franchised Chevrolet or GMC dealer to schedule the engine-block-heater and heater-cord replacement. Reference GM recall number 212329840 when you call.
Is the recall repair free?
Yes. Federal recall law requires the defect repair at no cost, and GM says dealers will replace the engine block heaters and heater cords free of charge. For trucks previously included in recall 19V328, the heater cord will be replaced and rerouted for free.
What is the safety risk?
The safety risk is fire. GM reported that an electrical short-circuit can occur in the engine-block heater cable or in the terminals that connect the heater cable to the block heater. If your VIN is included, arrange the free dealer repair.
What if I bought this truck used?
The free recall repair still applies. Federal recall law follows the vehicle, not the first owner. Check your VIN to confirm whether your exact Silverado or Sierra is included, then call a franchised Chevrolet or GMC dealer with recall number 21V496 or GM number 212329840.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V496000 |
|---|---|
| Chevrolet customer service | 1-800-462-8782 |
| NHTSA recall # | 21V496 |
| NHTSA recall # (full) | 21V496000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Recall Report (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Document (PDF) (PDF)
- Download Misc. Document (PDF)
- Download Owner Notice (PDF)
- Download Recall Document (PDF) (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 20, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →