--- title: "2021 Hyundai Sonata Parts and Specs" description: "Everything for the 2021 Hyundai Sonata: oil type and capacity, battery group size, tire sizes, wiper blades, filters, service schedule, and common problems, verified, sourced, and in one place." url: "https://whichcarparts.com/cars/hyundai/sonata/2021" updated: "2026-08-21" --- # 2021 Hyundai Sonata parts and specs Everything you need to own and maintain this exact model year. Verified specifications, part numbers, and the problems that recur, in one place. DN8 (8th generation), 2020-2025, Mid-size sedan. ## Quick facts | Quick fact | Value | | --- | --- | | Engine oil | 0W-20, 6.1 qt (base engine) | | Battery | Group 48 (H6) AGM | | Tire size | 205/65R16 (base trim) | | Wiper blades | 26" / 18" | | Cabin filter | 97133-L0000 (gas); 97133-N9100 (Hybrid) | | Key fob battery | CR2032 | ## Specifications for the 2020-2025 Sonata ### Oil & filter Viscosity, capacity, filter part numbers, change interval [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/oil). ### Battery BCI group size, cold cranking amps, AGM or flooded [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/battery). ### Tires & wheels Factory sizes by trim, pressures, bolt pattern, lug torque [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/tires). ### Wiper blades Driver, passenger and rear blade lengths [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/wipers). ### Air & cabin filters Cabin and engine air filter part numbers, locations, intervals [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/filters). ### Bulbs Headlight, fog and marker bulb types [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/bulbs). ### Brakes Rotor diameters, pad references, service notes [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/brakes). ### Fluids Transmission fluid, coolant, brake fluid and capacities [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/fluids). ### Service schedule What's actually due at every mileage interval [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/service-schedule). ### Problems & reliability Documented failures, recalls, and which years to avoid [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/common-problems). ### Oil light reset Step-by-step maintenance light reset, no tools [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/oil-reset). ### Key fob battery Which coin cell the remote takes [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/key-fob-battery). ### Specs Towing, weight, fuel tank, fuel economy [Read more](https://whichcarparts.com/cars/hyundai/sonata/2020-2025/specs). These specifications are shared across every Sonata of the DN8 (8th generation) generation. See the [2020-2025 Hyundai Sonata overview](https://whichcarparts.com/cars/hyundai/sonata/2020-2025) for the full picture, or the [Hyundai Sonata guide](https://whichcarparts.com/cars/hyundai/sonata) to compare every generation. ## What changed for the 2021 Hyundai Sonata | Years | What changed | | --- | --- | | 2021 | N Line trim introduced with the 2.5T Smartstream engine; 1.6T dropped from most trims | ## Known problems with the 2021 Hyundai Sonata 2 of the 2 issues we track for the 2020-2025 generation are documented against the 2021 model year. ### 2.5L Smartstream (G4KN) oil dilution and oil consumption (moderate) The base 2.5L Smartstream engine has a reported pattern of unburned fuel diluting the engine oil (lowering its viscosity and lubricating ability) along with above-average oil consumption, which some independent repair shops and parts suppliers attribute to a piston-ring design issue. Owners are advised to check oil level and condition between changes rather than assume the interval is safe to stretch. No dedicated NHTSA recall covers this as of this review. Typical cost: $0 (monitoring/top-offs) to $4,000+ for engine work if wear becomes severe. ### N Line oil-cap vs. owner's-manual viscosity confusion (minor) The 2.5T N Line's oil fill cap is marked 0W-20, but the owner's manual for this specific powertrain specifies 0W-30 as the factory-fill viscosity, a discrepancy widely discussed among owners and independent shops, some of whom have used the wrong oil as a result. Not a mechanical defect, but a documented source of incorrect oil-change service. Typical cost: N/A, verify viscosity against the owner's manual, not the cap, before an oil change. Full detail, costs and sources on the [Hyundai Sonata problems and years to avoid](https://whichcarparts.com/cars/hyundai/sonata/common-problems) guide. ## Which engines were offered in the 2021 Sonata? | Engine | Trims | Oil | Oil capacity | | --- | --- | --- | --- | | 2.5L 4-cylinder (Smartstream G4KN GDI) | SE, SEL, Limited (2.5L) | 0W-20 | 6.1 qt | | 1.6L Turbo 4-cylinder (Smartstream G1.6 T-GDI) | Limited 1.6T | 0W-20 | 5.1 qt | | 2.5L Turbo 4-cylinder (Smartstream G2.5 T-GDI, N Line) | N Line | 0W-30 | 6.1 qt | | 1.6L Turbo Hybrid (Smartstream G1.6 T-GDI + electric motor) | Hybrid, Hybrid Limited, Hybrid Blue | 0W-20 | 5.1 qt | ## About the Hyundai Sonata The Hyundai Sonata is the brand's midsize sedan and, for much of the 2011-2025 span covered here, a cautionary tale about engine manufacturing quality alongside genuinely good value. 0T GDI engines are the center of Hyundai's biggest-ever US recall saga: manufacturing debris left in connecting-rod oil passages caused a wave of engine seizures and fires, triggering two NHTSA recalls (15V-568, then the broader 17V-226), a Knock Sensor Detection System (KSDS) software campaign, and, after a November 2020 NHTSA consent order found Hyundai and Kia had moved too slowly and misreported data, a lifetime engine warranty extension for affected owners who install the KSDS update. The same generation's Sonata Hybrid was separately recalled (23V-651) for an ABS module that could short-circuit and start an engine-bay fire, with owners told to park outside. 0L hybrid/PHEV; Theta-family warranty coverage extends into its early years. 0L) shared with the Sonata Hybrid/Hybrid Limited. 3. Because of the recall history, checking a Sonata's VIN against NHTSA and Hyundai's recall lookup before buying or servicing one is more important here than on almost any other nameplate in this database. For how the specifications changed across every generation, see the [full Hyundai Sonata guide](https://whichcarparts.com/cars/hyundai/sonata). ## Other Hyundai Sonata years - [2025](https://whichcarparts.com/cars/hyundai/sonata/2025) - [2024](https://whichcarparts.com/cars/hyundai/sonata/2024) - [2023](https://whichcarparts.com/cars/hyundai/sonata/2023) - [2022](https://whichcarparts.com/cars/hyundai/sonata/2022) - [2020](https://whichcarparts.com/cars/hyundai/sonata/2020) - [2019](https://whichcarparts.com/cars/hyundai/sonata/2019) - [2018](https://whichcarparts.com/cars/hyundai/sonata/2018) - [2017](https://whichcarparts.com/cars/hyundai/sonata/2017) - [2016](https://whichcarparts.com/cars/hyundai/sonata/2016) - [2015](https://whichcarparts.com/cars/hyundai/sonata/2015) - [2014](https://whichcarparts.com/cars/hyundai/sonata/2014) - [2013](https://whichcarparts.com/cars/hyundai/sonata/2013) - [2012](https://whichcarparts.com/cars/hyundai/sonata/2012) - [2011](https://whichcarparts.com/cars/hyundai/sonata/2011) Data confidence for this generation: Verified. ## Sources - [Wikipedia, Hyundai Smartstream engine family (G1.6T, G1.6T Hybrid, displacement/output data)](https://en.wikipedia.org/wiki/Hyundai_Smartstream_engine) - [AMSoil lookup, 2022 Sonata 2.5L oil viscosity/capacity](https://www.amsoil.com/lookup/auto-and-light-truck/2022/hyundai/sonata/2-5l-4-cyl-engine-code-a-a/) - [Costa Oils, 2023 Sonata 2.5L Turbo (N Line) oil guide](https://costaoils.com/2023-hyundai-sonata-2-5l-turbo-oil-change-guide-2/) - [Hyundai Forums, N Line owner's manual 0W-30 vs. 0W-20 cap discussion](https://www.hyundai-forums.com/threads/0w-20-oil-only-one-listed.671641/) - [Goodyear, 2024 Sonata factory tire fitments by trim](https://www.goodyear.com/en-us/vehicles/Hyundai/Sonata/2024) - [Headquarter Hyundai, 2020 Sonata fuel tank capacity and EPA mpg](https://www.headquarterhyundai.com/research/2020-hyundai-sonata-mpg/) - [US News, 2021 Sonata Limited 1.6T engine specs](https://cars.usnews.com/cars-trucks/hyundai/sonata/2021/specs/sonata-limited-1-6t-416162) - [Go-Parts, 2021-2024 Hyundai/Kia 2.5L Smartstream (G4KN) oil dilution/piston-ring notes](https://www.go-parts.com/garage/engine-complete-assembly-kia-sorento-hyundai-santa-fe-hyundai-sonata-2021-2024) Specifications vary with engine option, production date, and market.