Hyundai and Kia engines: Theta II, 2.5T, Smartstream and V6
By CarWhere Research · Updated
Hyundai and Kia share their engines: the Theta II 2.4L and 2.0T (the subject of the engine recalls and class settlement), the Nu and Gamma fours, the newer Smartstream family including the 2.5L turbo, the Lambda V6 and the E-GMP electric platform. CarWhere covers 7 engines and platforms with years, ratings, 22 documented problems and 52 NHTSA recalls.
One page serves every Hyundai and Kia that uses an engine — the 2.4L Theta II, for example, appears in versions of the Sonata, Santa Fe Sport, Optima, Sorento and Sportage. Each page lists the model years, manufacturer-published output by application, design facts, documented problems with pre-purchase checks, and verified NHTSA recall campaigns. Related: Hyundai engine settlement, Kia engine settlement and the Kia research hub.
Four-cylinder engines
| Engine | Model years | Peak output | Known problems | Recalls |
|---|---|---|---|---|
| Theta II (2.4L and 2.0T)Hyundai/Kia Theta II inline-four: 2.4L GDI, 2.0L turbo GDI and 2.4L MPI (US 2010–2022) | 2011–2022 · 2010–2016 | — | 4 | 11 |
| Nu (1.8L and 2.0L)Hyundai/Kia Nu inline-four: 1.8L MPI, 2.0L GDI and 2.0L MPI (US 2011–2021) | 2011–2016 · 2014–2021 · 2017–2023 | — | 3 | 6 |
| Gamma 1.6L (GDI and Turbo-GDI)Hyundai/Kia Gamma 1.6L inline-four: 1.6 GDI and 1.6 Turbo-GDI (US 2012–2022) | 2012–2019 · 2013–2022 | — | 3 | 4 |
| Smartstream (G1.6T, G2.0, G2.5)Hyundai/Kia Smartstream gasoline engines: G1.6 T-GDi (gas and hybrid), G2.0 MPI with IVT, G2.5 GDi + MPI and G1.6 MPI (US 2020–present) | 2020–present · 2020–present · 2020–present · 2020–present | 268 hp / 271 lb-ft | 2 | 3 |
| Smartstream G2.5 T-GDi (2.5 turbo)Hyundai/Kia Smartstream G2.5 T-GDi 2,497 cc turbocharged inline-four, gas and hybrid (US 2021–present) | 2021–present · 2026–present | 329 hp / 339 lb-ft | 2 | 6 |
- Theta II (2.4L and 2.0T) years, specs and problems — Theta II is the Hyundai–Kia inline-four family behind the 2.4L GDI and 2.0L turbo GDI engines in 2011–2019 Sonata, Santa Fe Sport, Tucson, Optima, Sorento and Sportage models.
- Nu (1.8L and 2.0L) years, specs and problems — Nu is the Hyundai–Kia 1.8L and 2.0L four-cylinder family used in the Elantra, Forte, Soul, Tucson, Kona and Veloster.
- Gamma 1.6L (GDI and Turbo-GDI) years, specs and problems — Gamma is Hyundai and Kia's 1.6L four-cylinder family.
- Smartstream (G1.6T, G2.0, G2.5) years, specs and problems — Smartstream is the name Hyundai uses for its current engine family.
- Smartstream G2.5 T-GDi (2.5 turbo) years, specs and problems — The 2.5 turbo is Hyundai and Kia's Smartstream G2.5 T-GDi, a 2,497 cc turbocharged four with direct and port injection.
V6 engines
| Engine | Model years | Peak output | Known problems | Recalls |
|---|---|---|---|---|
| Lambda V6 (3.3, 3.5, 3.8L)Hyundai/Kia Lambda V6 family: 3.3L GDI, 3.8L GDI, 3.5L MPI + GDI and earlier MPI V6s (US 2007–present) | 2020–2025 · 2012–2021 · 2022–present · 2007–2014 | 287 hp / 260 lb-ft | 4 | 9 |
- Lambda V6 (3.3, 3.5, 3.8L) years, specs and problems — Lambda is the Hyundai–Kia V6 family.
Electric platform
| Engine | Model years | Peak output | Known problems | Recalls |
|---|---|---|---|---|
| E-GMP (Electric Global Modular Platform)Hyundai Motor Group E-GMP dedicated EV platform: Ioniq 5, Ioniq 6, Ioniq 9, Kia EV6, EV9 and Genesis GV60 (US 2022–present) | 2022–present · 2022–present | 601 hp / 545 lb-ft | 4 | 13 |
- E-GMP (Electric Global Modular Platform) years, specs and problems — E-GMP (Electric Global Modular Platform) is Hyundai Motor Group's dedicated EV platform.
Know which engine and transmission a car was built with.
Hyundai and Kia build the same model with several engines, outputs and drivetrains. The CarWhere Hyundai build sheet reconstructs factory colors, options and packages from licensed VIN-level build data — availability is checked free, and it is $9.99 only when detailed build data is found for that VIN.
Frequently asked questions
Which Hyundai and Kia engines were recalled for engine failure?
Theta II is the Hyundai–Kia inline-four family behind the 2.4L GDI and 2.0L turbo GDI engines in 2011–2019 Sonata, Santa Fe Sport, Tucson, Optima, Sorento and Sportage models. Its defining issue is connecting-rod bearing wear, handled through recalls, the KSDS software update and a lifetime short-block warranty under a 2021 class settlement.
Is the Hyundai/Kia 2.5 turbo a Theta engine?
The 2.5 turbo is Hyundai and Kia's Smartstream G2.5 T-GDi, a 2,497 cc turbocharged four with direct and port injection. It makes 274–290 hp and 311 lb-ft in 2027 models and anchors the Palisade and Telluride hybrids. Its recalls so far cover leaking fuel-pipe connections on 2021–2022 cars and a few turbo oil-pipe cracks.
What is a Smartstream engine?
Smartstream is the name Hyundai uses for its current engine family. In US models that means a 2.5L GDI + MPI four rated at 186–191 hp, a 1.6L turbo used alone (190–201 hp) and in hybrids (231–232 hp combined), a 2.0L MPI with an IVT (147 hp) and a 1.6L MPI in the Venue (121 hp).
What is E-GMP?
E-GMP (Electric Global Modular Platform) is Hyundai Motor Group's dedicated EV platform. Kia lists it on the EV9 spec sheet and Hyundai uses it for the Ioniq 5. These EVs support 800V ultra-fast charging, with 149–601 hp from one or two motors. Their main recall is the integrated charging control unit (ICCU), which can stop charging the 12V battery.
Do Hyundai and Kia use the same engines?
Yes. Hyundai Motor Company and Kia share engine families and platforms, so the same engine page covers, for example, a Hyundai Sonata and a Kia Optima with the same 2.4L Theta II. Output can differ by model and year, so each page lists ratings per application.
How do I find out which engine my Hyundai or Kia has?
The engine is encoded in the VIN, and the build record lists the engine and transmission the vehicle was built with. A free VIN decoder shows the basic engine; a build sheet adds factory options and packages.
Sources
Each engine page lists its own detailed sources. Key references across the guide:
- Hyundai Motor America newsroom — specifications and model-year changes — Hyundai Motor America
- Recalls Data (NHTSA recall campaigns) — U.S. Department of Transportation open data
- NHTSA recalls database — National Highway Traffic Safety Administration
- NHTSA recall 15V568: Connecting rod wear may result in engine stall (2011–2012 Sonata) — NHTSA (Hyundai Motor America filing)
- NHTSA recall 17V226: Bearing wear may result in engine seizure (2013–2014 Sonata, Santa Fe Sport) — NHTSA (Hyundai Motor America filing)
- NHTSA recall 17V224: Bearing wear may result in engine seizure (2011–2014 Optima, 2012–2014 Sorento, 2011–2013 Sportage) — NHTSA (Kia America filing)
- NHTSA recall 18V934: High-pressure fuel pipe may leak (Hyundai engines replaced under 15V-568/17V-226) — NHTSA (Hyundai Motor America filing)
- NHTSA recall 18V907: High-pressure fuel pipe may leak (Kia engines replaced under 17V-224, warranty or KSDS campaign) — NHTSA (Kia America filing)
- NHTSA recall 20V121: Low-pressure fuel hose may crack and leak (2013–2014 Sonata) — NHTSA (Hyundai Motor America filing)
- NHTSA recall 22V312: Low-pressure fuel hose may crack and leak (2013–2014 Sonata, replacement remedy) — NHTSA (Hyundai Motor America filing)
- NHTSA recall 20V100: Low-pressure fuel hose may crack and leak (2013–2014 Optima 2.4L GDI / 2.0L GDI Turbo) — NHTSA (Kia America filing)
More Hyundai tools
- Hyundai research hub
- Hyundai trim levels explained
- Hyundai known issues by model
- Hyundai history
- Hyundai warranty
- Hyundai engine settlement
- Hyundai anti-theft software update
- Free Hyundai VIN decoder
- Hyundai specs by model
- Hyundai reliability
- How long do Hyundai models last?
- Hyundai invoice vs what buyers paid
- Hyundai build sheet by VIN
- Genesis (Hyundai’s luxury brand)
Independent reference compiled by CarWhere — not affiliated with or endorsed by Hyundai Motor America, Hyundai Motor Company or Hyundai Motor Group. Hyundai and the model names are trademarks of their owners.