Engine Code

HYUNDAI G4KC engine (2020–2024) – Specs, Problems & Compatibility Database

The Hyundai G4KC is a 1,497 cc, inline‑four naturally aspirated petrol engine introduced in 2020 as part of Hyundai’s Smartstream G1.5 engine family. It features dual overhead camshafts (DOHC), 16 valves, and Hyundai’s Dual Continuously Variable Valve Timing (D‑CVVT) system. In standard form it delivers 88–90 kW (120–122 PS) with torque between 147–151 Nm, prioritizing urban efficiency and low emissions for compact hatchbacks and crossovers.

Fitted to models such as the i20 (PB), Bayon, and Kona (OS), the G4KC was engineered for responsive city driving, fuel economy, and compliance with Euro 6d emissions standards. Emissions control is achieved through a close-coupled three-way catalyst, cooled exhaust gas recirculation (EGR), and precise electronic throttle management.

One documented concern is occasional rough idle or hesitation linked to intake valve carbon buildup in vehicles with frequent short trips. This issue was noted in Hyundai Technical Service Bulletin TSB-21-EM-008, which recommends updated ECU calibration and periodic intake system inspection for affected production batches.

BMW N47D20A Engine
Compliance Note:

All production years 2020–2024 meet Euro 6d standards (VCA UK Type Approval #VCA/EMS/9245).

G4KC Technical Specifications

The Hyundai G4KC is a 1,497 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and subcompact SUVs (2020–2024). It combines DOHC architecture with Dual CVVT and Smartstream thermal efficiency enhancements to deliver smooth low‑rpm response and reduced fuel consumption. Designed to meet stringent Euro 6d emissions standards, it balances urban drivability with low maintenance demands.

ParameterValueSource
Displacement1,497 cc
Fuel typePetrol (Unleaded)
ConfigurationInline‑4, DOHC, 16‑valve
AspirationNaturally aspirated
Bore × stroke75.5 mm × 83.5 mm
Power output88–90 kW (120–122 PS) @ 6,200 rpm
Torque147–151 Nm @ 4,500 rpm
Fuel systemMulti-point fuel injection (MPi)
Emissions standardEuro 6d
Compression ratio12.0:1
Cooling systemWater‑cooled
TurbochargerNone
Timing systemChain-driven DOHC
Oil typeHyundai Genuine 0W‑20 (API SP/ILSAC GF‑6)
Dry weight105 kg
Practical Implications

The high 12.0:1 compression ratio enhances thermal efficiency but demands precise fuel quality and oil specification. Hyundai Genuine 0W-20 (API SP) oil is essential to protect the timing chain and maintain valve train smoothness. Engines used predominantly for short urban trips may accumulate carbon on intake valves due to lack of sustained high-temperature operation; periodic intake inspection is advised per TSB-21-EM-008. The timing chain is designed for life but relies on clean, low-viscosity oil—extended intervals or incorrect viscosity increase wear risk. Fuel injectors are robust but benefit from Top Tier petrol to minimize deposit formation.

Data Verification Notes

Oil Specs: Requires Hyundai Genuine 0W-20 meeting API SP/ILSAC GF-6 (Hyundai SIB TSB-21-EM-008).

Emissions: Euro 6d certification applies to all G4KC production years (VCA Type Approval #VCA/EMS/9245).

Power Ratings: Measured under SAE J1349 standards. Power varies by model calibration (Hyundai TIS Doc. HEM-G4KC-04).

Primary Sources

Hyundai Technical Information System (TIS): Docs HEM-G4KC-01 through HEM-G4KC-04, TSB-21-EM-008

VCA Type Approval Database (VCA/EMS/9245)

SAE International: J1349 Engine Power Certification Standards

G4KC Compatible Models

The Hyundai G4KC was used across Hyundai's PB/OS platforms with transverse mounting and shared with Kia under the Hyundai–Kia alliance. This engine received platform-specific adaptations—revised engine mounts in the Bayon and modified intake manifolds in the i20 PB—and from 2021 onward, all applications retained identical calibration but with model-specific ECU part numbers. Partnerships enabled Kia Stonic facelift variants to use identical powertrains. All adaptations are documented in OEM technical bulletins.

Make:
Hyundai
Years:
2020–2024
Models:
i20 (PB)
Variants:
1.5 MPi
View Source
Hyundai ETK Doc. H20‑6128
Make:
Hyundai
Years:
2021–2024
Models:
Bayon
Variants:
1.5 MPi
View Source
Hyundai TIS Doc. HEM-G4KC-05
Make:
Hyundai
Years:
2020–2024
Models:
Kona (OS)
Variants:
1.5 MPi
View Source
Hyundai Group PT‑2023
Make:
Kia
Years:
2021–2024
Models:
Stonic (YB facelift)
Variants:
1.5 MPi
View Source
Kia EPC #KJ-G4KC-2021
Identification Guidance

Locate the engine code stamped on the front-left side of the block near the timing cover (Hyundai TIS HEM-G4KC-02). The 7th VIN digit for Hyundai i20 PB is 'F' for 1.5L MPi variants. All G4KC units feature black valve covers with integrated oil filler cap and lack direct injection rails. Critical differentiation from Smartstream G1.5 T-GDi (G4LH): G4KC uses MPi (not GDi), has no high-pressure fuel pump on cam cover, and exhibits simpler intake manifold. Service parts are generally consistent across model years, but ECU calibration varies—verify part number before replacement (Hyundai TSB-21-EM-008).

Identification Details

Evidence:

Hyundai TIS Doc. HEM-G4KC-02

Location:

Stamped on front-left engine block near timing cover (Hyundai TIS HEM-G4KC-02).

Visual Cues:

Black valve cover, MPi throttle body (no high-pressure fuel pump)
Carbon Buildup Advisory

Issue:

Vehicles with frequent short trips may develop intake valve carbon deposits, causing rough idle or hesitation.

Evidence:

Hyundai TSB-21-EM-008

Recommendation:

Inspect intake system every 60,000 km; apply updated ECU calibration per TSB-21-EM-008 if symptoms occur.

Common Reliability Issues - HYUNDAI G4KC

The G4KC's primary reliability risk is intake valve carbon buildup in urban-use vehicles, with elevated incidence in high-short-trip applications. Hyundai internal field data from 2022 indicated a subset of engines required intake service before 70,000 km, while UK DVSA records show excellent emissions compliance due to robust Euro 6d certification. Infrequent highway driving and use of non-Top Tier fuel increase deposit formation, making periodic inspection critical.

Intake valve carbon buildup
Symptoms: Rough idle, hesitation on light throttle, occasional misfire codes (P0300–P0304), reduced fuel economy.
Cause: Oil vapor from crankcase ventilation mixing with fuel vapors in MPi system, forming carbon deposits on intake valves during low-temperature operation.
Fix: Clean intake manifold and valves using chemical methods; apply updated ECU calibration per Hyundai TSB-21-EM-008.
PCV valve clogging
Symptoms: Increased crankcase pressure, oil leaks from seals, whistling noise from valve cover.
Cause: Accumulation of sludge in positive crankcase ventilation valve due to infrequent oil changes or short-trip driving.
Fix: Replace PCV valve with latest OEM part; inspect and clean breather hoses; maintain 10,000 km oil intervals with 0W-20 oil.
Throttle body contamination
Symptoms: Sticky throttle response, idle fluctuation, stored P2111/P2112 codes.
Cause: Carbon and oil residue buildup on throttle plate and bore from crankcase vapors.
Fix: Clean throttle body with OEM-approved solvent; perform throttle adaptation using GDS2 diagnostic tool.
Engine mount wear
Symptoms: Increased vibration at idle, clunk on gear engagement, visible rubber cracking.
Cause: Age-related hardening of hydraulic engine mounts, accelerated by heat exposure in compact engine bays.
Fix: Replace all mounts as a set using OEM hydraulic units to restore NVH performance.
Research Basis

Analysis derived from Hyundai technical bulletins (2020–2023) and UK DVSA failure statistics (2021–2024). Repair procedures should follow manufacturer guidelines.

Frequently Asked Questions about HYUNDAI G4KC

Find answers to most commonly asked questions about HYUNDAI G4KC.

Research Resources

Comprehensive technical documentation and regulatory references

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Last Updated: 16 August 2025

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