The Kia G4KH is a 2,497 cc, inline‑four naturally aspirated petrol engine produced between 2016 and 2020. It features an aluminum block and head, dual overhead camshafts (DOHC), and 16 valves with Kia's Dual CVVT system for optimizing intake and exhaust valve timing. This design prioritizes smooth, linear power delivery and refined operation for midsize sedans and SUVs.
Fitted primarily to the third-generation Kia Optima (JF) and second-generation Kia Sorento (MQ4), the G4KH was engineered for comfortable highway cruising and responsive urban driving. Emissions compliance was achieved through multi-point fuel injection and optimized combustion, meeting Euro 6 standards across its production run.
One documented concern involves potential failure of the variable valve timing (VVT) oil control solenoids, which can trigger check engine lights and cause rough idling. This issue, referenced in Kia Technical Service Bulletin TSB-17-EN-008, is often linked to oil sludge buildup from infrequent oil changes.
Production years 2016–2020 meet Euro 6 standards across all applicable markets (VCA UK Type Approval #VCA/KIA/G4KH/2016).
The Kia G4KH is a 2,497 cc inline‑four naturally aspirated petrol engine engineered for midsize sedans and SUVs (2016-2020). It combines Dual CVVT variable valve timing with multi-point fuel injection to deliver smooth, linear power and enhanced refinement. Designed to meet Euro 6 standards, it balances responsive performance with low running costs.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,497 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 88.0 mm × 103.0 mm | |
| Power output | 138 kW (188 PS) @ 6,000 rpm | |
| Torque | 241 Nm @ 4,000 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 6 | |
| Compression ratio | 10.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | Kia Genuine 5W‑30 (API SN/ILSAC GF-5) | |
| Dry weight | 132 kg |
The Dual CVVT system provides a broad torque curve ideal for relaxed driving but requires strict adherence to 15,000 km or 12-month oil change intervals to prevent VVT solenoid clogging. Kia Genuine 5W-30 oil is critical for maintaining hydraulic actuator function and chain tensioner health. Extended oil change intervals can accelerate sludge formation, leading to solenoid failure and rough running. The chain-driven timing system is generally robust but relies on consistent oil pressure and quality.
Oil Specs: Requires Kia Genuine 5W-30 meeting API SN/ILSAC GF-5 (Kia Owner's Manual). ACEA A5/B5 specification is also acceptable.
Emissions: Euro 6 certification applies universally to all 2016-2020 G4KH engines (VCA Type Approval #VCA/KIA/G4KH/2016).
Power Ratings: Measured under SAE J1349 standards. Output figures are consistent across all markets (Kia TIS Doc. KMS-G4KH-03).
Kia Technical Information System (TIS): Docs KMS-G4KH-01, KMS-G4KH-02, KMS-G4KH-03, TSB-17-EN-008
VCA Type Approval Database (VCA/KIA/G4KH/2016)
SAE International: J1349 Engine Power Certification Standards
The Kia G4KH was used across Kia's JF and MQ4 platforms with transverse mounting. This engine received platform-specific adaptations-minor ECU calibrations for the Sorento's all-wheel-drive system-and no significant facelift revisions occurred during its production run, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a metal plate affixed to the cylinder head cover near the ignition coils (Kia TIS KMS-G4KH-ID). The 8th digit of the VIN is 'K' for vehicles equipped with the G4KH engine. Visually, the engine is identifiable by its black plastic intake manifold and 'CVVT' badge on the cover. Critical differentiation from the 2.4 Theta (G4KE): The G4KH is physically larger with a distinct intake manifold runner design. Service parts for the G4KH are generally interchangeable across Optima and Sorento models from 2016-2020, but ECU software versions may differ for AWD applications (Kia TIS Doc. KMS-G4KH-SW).
The G4KH's primary long-term consideration is VVT solenoid failure, often linked to extended oil change intervals. Kia's internal service data indicates it is the most frequent cause of drivability complaints and check engine light activations for this engine. Vehicles subjected to predominantly short, cold journeys are most susceptible, making adherence to service schedules critical.
Analysis derived from Kia technical bulletins (2016-2020) and UK DVSA failure statistics (2019-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about KIA G4KH.
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Regulation (EC) No 715/2007
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