The Hyundai G4KH is a 1,591 cc, inline‑four naturally aspirated petrol engine produced between 2015 and 2023. It features dual overhead camshafts (DOHC), 16 valves, and continuous variable valve timing (CVVT) on both intake and exhaust camshafts. In standard form it delivered 94–95 kW (128–129 PS) and torque figures between 156–157 Nm, optimized for urban efficiency and smooth low‑rpm response.
Fitted to models such as the i20 (PB), i30 (PD), and Kona (OS), the G4KH was e…
Hyundai
All production years 2015–2023 meet Euro 6 standards (VCA UK Type Approval #VCA/EMS/7890).
The Hyundai G4KH is a 1,591 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and crossovers (2015–2023). It combines DOHC architecture with dual CVVT to deliver responsive low-end torque and quiet operation. Designed to meet Euro 6 emissions standards, it balances drivability with urban fuel efficiency and regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,591 cc | |
Fuel type | Petrol (Unleaded, RON 95 min) | |
Configuration | Inline‑4, DOHC, 16‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 77.0 mm × 85.4 mm | |
Power output | 94–95 kW (128–129 PS) | |
Torque | 156–157 Nm @ 4,850 rpm | |
Fuel system | Multi-point fuel injection (MPFI) | |
Emissions standard | Euro 6 | |
Compression ratio | 10.5:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | Hyundai SP 5W‑20 or 5W‑30 (API SN/ILSAC GF-5) | |
Dry weight | 115 kg |
The Hyundai G4KH was used across Hyundai's PB/PD/OS platforms with transverse mounting and no hybrid variants. This engine received platform-specific intake manifolds—acoustic tuning in the i20, revised EGR routing in the Kona, and optimized airflow in the i30—and from 2019 the ECU calibration update improved deposit resistance, creating service part distinctions. All adaptations are documented in OEM technical bulletins.
The G4KH's primary reliability risk is intake valve carbon buildup in high-mileage or stop-start urban use, stemming from its port-fuel injection design. Hyundai internal service data from 2018 indicated a measurable subset of early engines exhibiting rough idle and reduced efficiency after 80,000 km, while UK DVSA records show no significant emissions-related MOT failures tied to this engine. Extended oil change intervals and short-trip driving amplify deposit formation, making maintenance adherence critical.
Analysis derived from Hyundai technical bulletins (2016–2021) and UK DVSA failure statistics (2018–2023). Repair procedures should follow manufacturer guidelines.
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The G4KH is generally dependable for daily driving, but high-mileage units may develop intake valve carbon deposits due to its port-fuel injection design. Post-2019 models feature updated calibration that reduces this risk. Regular oil changes with correct 5W‑20/30 SP spec oil and occasional highway driving help maintain performance and longevity.
Top issues include intake valve carbon buildup, CVVT solenoid clogging, timing chain tensioner wear, and EGR valve sticking. These are documented in Hyundai TSBs and addressed with updated service procedures. Most problems are preventable with proper maintenance and correct oil.
The G4KH powered the i20 (PB, 2015–2020), i30 (PD, 2017–2023), and Kona (OS, 2017–2023). All are non-hybrid, Euro 6 compliant, and use transverse mounting with DOHC and dual CVVT on both camshafts.
Limited tuning potential. As a naturally aspirated 1.6L engine, gains are modest—typically +5–7 kW via ECU remap and intake/exhaust upgrades. No factory turbo variants exist, and internal components are not designed for significant forced induction.
In an i30 1.6 MPi, expect ~7.5 L/100km city and ~5.0 L/100km highway (~47 mpg UK combined). Real-world figures vary with driving style, but the engine is optimized for urban efficiency and smooth cruising.
Yes. The G4KH is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can cause catastrophic damage. Regular inspection of the chain tensioner and using correct oil viscosity are critical to prevent failure.
Hyundai specifies SP 5W‑20 or 5W‑30 synthetic oil meeting API SN/ILSAC GF-5 or newer. Always use low-SAPS oil to protect emissions components and valve train. Change every 10,000 km or 12 months.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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