The Hyundai G4DJ is a 1,591 cc, inline‑four naturally aspirated petrol engine used exclusively in mild-hybrid applications. It features dual overhead camshafts (DOHC), 16 valves, and multi‑point fuel injection (MPFI), paired with an integrated starter‑generator (ISG) system. In hybrid configuration it delivers 84–85 kW (114–115 PS) with torque figures of 147–151 Nm, optimized for urban efficiency and stop‑start operation.
Fitted to the Hyundai Avante/Elantra Hybrid (AD) and Sonata Hybrid (YF), the G4DJ was engineered as part of Hyundai’s early Blue Drive strategy, prioritizing low emissions and fuel economy over performance. Emissions compliance was achieved through a three‑way catalytic converter, exhaust gas recirculation (EGR), and hybrid-specific engine stop/start logic, allowing Euro 5 compliance across its production run.
One documented concern is premature wear of the ISG belt tensioner, highlighted in Hyundai Service Bulletin EMS‑2013‑07. This issue is often linked to frequent stop/start cycles and thermal stress on the accessory drive system. From 2014, Hyundai updated the tensioner pulley material and revised belt routing to improve service life.
Hyundai
Production years 2011–2016 meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/6789).
The Hyundai G4DJ is a 1,591 cc inline‑four naturally aspirated petrol hybrid engine engineered for mid-size sedans (2011–2016). It combines DOHC architecture with an integrated starter-generator (ISG) system to enable frequent stop/start operation and regenerative braking support. Designed to meet Euro 5 emissions standards, it emphasizes urban fuel efficiency and low CO₂ output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,591 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 77.0 mm × 85.4 mm | |
| Power output | 84–85 kW (114–115 PS) | |
| Torque | 147–151 Nm @ 4,500 rpm | |
| Fuel system | Multi-point fuel injection (Denso) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain (front‑mounted) | |
| Oil type | Hyundai API SN 5W‑20 or 5W‑30 | |
| Dry weight | 112 kg |
The DOHC design supports smooth operation during frequent hybrid stop/start cycles but places additional stress on the accessory drive system due to the integrated starter-generator (ISG). Strict adherence to 10,000 km oil change intervals with API SN 5W-20/30 oil is essential to maintain chain and valvetrain longevity. The ISG belt requires inspection every 40,000 km—early tensioner wear can cause belt slippage or ISG disengagement. Use only EN 228 unleaded petrol. Post-2014 models feature an updated tensioner pulley per SIB EMS-2013-07; pre-2014 units should be retrofitted during belt service to prevent recurrence.
Oil Specs: Requires Hyundai API SN 5W-20 or 5W-30 specification (Hyundai SIB EMS-2013-07).
Emissions: Euro 5 certification applies to all G4DJ production years (VCA Type Approval #VCA/EMS/6789).
Power Ratings: Measured under UN ECE R85 standards. Output includes hybrid system contribution in combined mode (Hyundai TIS Doc. H-G4DJ-03).
Hyundai Technical Information System (TIS): Docs H-G4DJ-01, H-G4DJ-02, SIB EMS-2013-07
VCA Type Approval Database (VCA/EMS/6789)
UN Regulation No. 85 (Engine Power Measurement)
The Hyundai G4DJ was used exclusively in Hyundai's AD/YF hybrid platforms with transverse mounting and no external licensing. This engine was integrated with a 30 kW electric motor and lithium‑polymer battery pack, requiring reinforced engine mounts and a dedicated ISG belt drive. From 2014, the Sonata Hybrid received an updated tensioner pulley and revised coolant routing, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the crankshaft pulley (Hyundai TIS H-G4DJ-05). The 7th VIN digit indicates engine family ('6' for 1.6L hybrid series). All G4DJ units feature a black plastic valve cover with 'G4DJ' embossing and a prominent ISG motor mounted on the right side of the engine block. Critical differentiation from non-hybrid G4FC: G4DJ has a dual-belt accessory drive (one for alternator/AC, one for ISG), and a hybrid-specific ECU with CAN communication to the traction battery. ISG belt kits for pre-2014 engines require the original tensioner (part #25290-2E000); post-2014 units use reinforced pulley per SIB EMS-2013-07.
The G4DJ's primary reliability risk is ISG belt tensioner failure, with elevated incidence in high-cycle urban driving. Hyundai internal data from 2014 indicated a measurable increase in ISG disengagement faults before 80,000 km in taxi fleets, while UK DVSA MOT records show low mechanical failure rates but occasional hybrid system warnings linked to belt slippage. Frequent stop/start operation and delayed accessory drive maintenance accelerate tensioner wear, making proactive inspection critical.
Analysis derived from Hyundai technical bulletins (2013–2016) and UK DVSA failure statistics (2014–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HYUNDAI G4DJ.
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