2021 Hyundai Sonata Hybrid Engine cooling Problems
- Complaints
- 3about this part
- Share
- 5%of 55 total for the year
- Median mileage
- 32,547miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 3 complaints about the engine cooling of the 2021 Hyundai Sonata Hybrid, 5% of the 55 complaints for this model year. Where a mileage was given, the median is 32,547 miles.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“Engine oil plug backed out while driving causing loss of all engine oil in the mountains. Drive time was one hour when oil lamp turned on as we reached our destination. Oil check stick had no oil on it and the whole undercarriage and rear of the car was covered in engine oil. Made an attempt to refill oil and plug fell all the way out and poured the new oil onto the ground. The oil plug is not visible or accessible due to a plastic cover on the underside of the car. …”
NHTSA complaint #11509128, filed 2023-02“The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, he received an alert indicating that the engine was overheating and to pull over. No warning lights were illuminated. The contact then veered to the side of the road and waited approximately 15 minutes before restarting the vehicle. The vehicle was then taken to the dealer where the vehicle remained. The vehicle was diagnosed, and it was determined that the engine coolant bypass valve needed to be replaced. The vehicle had not yet been repaired. …”
NHTSA complaint #11521686, filed 2023-05, 32,547 milesRelated service bulletins
- 10249698Jan 10, 2024This bulletin provides the procedure to update the Hybrid Control Unit (HCU) and Dual Automatic Temperature Control (DATC) software to help improve coolant flow to the Exhaust…
- 10247605Dec 15, 2023Certain 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles may exhibit coolant leakage, engine overheating, and white smoke from the exhaust due to an internal leak at the Exhaust Heat…
- 10247189Oct 13, 2023This bulletin provides important checkpoint guidelines when performing engine oil and filter change services.
- 10241883Aug 25, 2023This bulletin provides information related to the Engine Control Module (ECM) software update and coolant replacement for 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles to improve…
- 10218649Aug 17, 2022If you are servicing an applicable vehicle with a âCheck Engineâ light on and one or more of the DTC listed below, follow the Service Procedure and replace the valve body…
- 10217251Jul 28, 2022Follow the guidelines outlined in this bulletin to inspect and clean or replace certain components of the engine intake system accordingly during engine short block or…
- 10215602Jun 21, 2022If you are servicing an applicable vehicle with a âCheck Engineâ light on and one or more of the DTC listed below, follow the Service Procedure and replace the related…
- 10190044Mar 30, 2021This bulletin provides the service procedure for engine connecting rod bearing clearance testing. Perform the procedure outlined in this bulletin to fulfill the Bearing Clearance…
- 10189989Mar 10, 2021This bulletin provides the inspection procedure and repair guidelines for certain vehicles listed below.
Engine cooling: other model years
Other parts of the 2021 Hyundai Sonata Hybrid
25 complaintsEngine
21 complaintsOther or unknown
7 complaintsFuel system
5 complaintsTransmission and drivetrain
4 complaintsForward collision avoidance
3 complaintsBody and structure
1 complaintsTires
1 complaintsVisibility (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 30, 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