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EnginePart report

2021 Hyundai Sonata Hybrid Engine Problems

Complaints
21about this part
Share
38%of 55 total for the year
Median mileage
—not reported
Trend
RisingComplaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.

NHTSA recorded 21 complaints about the engine of the 2021 Hyundai Sonata Hybrid, 38% of the 55 complaints for this model year.

Example complaints

Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.

“Initially had loss of cabin heat. Later, vehicle randomly overheated. Repair shop replaced EGR due to finding confidant buildup of water/coolant mix. Within one week, problem returned. Dealer notified me that while replacing another part they found a TSB for coolant leakage into exhaust that was consistent with my issue. After research, it is clear that this is a widespread failure and should be a recall.”

NHTSA complaint #11571605, filed 2024-02

“My 2021 Hyundai Sonata Hybrid seems to be leaking coolant into the exhaust system. Various reports online indicate that this is a consistent issue with 2020-2022 Hyundai Sonata Hybrid models. A lot of the reports indicate that owners have tried getting theirs cars repaired for the same issue I have a various dealerships all across the US, but either haven't had any luck or have had a temporary fix for the issue, which proceeded to occur again every couple of months. …”

NHTSA complaint #11636925, filed 2025-01

“My car will power off randomly, or will seem as though there is no power. I have to revert back to the manual key to enter the vehicle and hit the 12vlt reset to power it back on. This happened at least 3 times. Once while operating the vehicle, and twice while the vehicle was left parked. This is not a low battery issue as, the car will only do this occasionally, and not every time I enter and turn on the vehicle. There is no error code to follow this mishap as all power goes out and the dealer maintenance has nothing to work with.”

NHTSA complaint #11592346, filed 2024-06

“The cabin heater started blowing cold air in February. One shop said the car was low on coolant and topped it off. I made an appointment to take the car to a dealer because it's still under warranty (<37k miles). I had to wait 3 weeks. A few days before my appointment, the cabin heater started blowing cold air, again. There is no indicator that the coolant is low. The engine temperature is one of a dozen gauges one can scroll thru, but the engine overheating warning started flashing before I thought to check the temperature guage. …”

NHTSA complaint #11515318, filed 2023-04

“While driving, engine alerted that it was overheating. Pulled over and coolant was very low, so I refilled it and then while driving to my family's garage to use the lift, saw white exhaust smoke. Took it to an independent mechanic, and in the ~10 mile trip there, over a quart of coolant had been burned off. He was able to reproduce the issue. No issues with the engine operation, it runs well and efficient, no check engine light. Mechanic found that a coolant line runs to the middle of the exhaust system and that this seems to be the issue. …”

NHTSA complaint #11558373, filed 2023-12

Related service bulletins

Engine: other model years

YearComplaintsShare of year
2024111%
2023747%
2022211%
20212138%
2020850%
2019360%
2018556%
20174657%
20167355%
20151935%
20141243%
20134037%
20126844%
20114042%

Other parts of the 2021 Hyundai Sonata Hybrid

Electrical system
25 complaints
Other or unknown
7 complaints
Fuel system
5 complaints
Transmission and drivetrain
4 complaints
Engine cooling
3 complaints
Forward collision avoidance
3 complaints
Body and structure
1 complaints
Tires
1 complaints
Visibility (wipers, defrost, mirrors)
1 complaints

← All problems reported for the 2021 Hyundai Sonata Hybrid

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 29, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology