The Hyundai G6AT is a 2,656 cc, V6 naturally aspirated petrol engine produced between 2002 and 2006. It features a dual overhead camshaft (DOHC), 24‑valve configuration and sequential multi‑point fuel injection (SFI), delivering 125 kW (170 PS) and 245 Nm of torque. Its design prioritised smooth power delivery and refinement for mid‑size sedans and SUVs.
Fitted to models such as the Sonata (NF), Santa Fe (SM), and Trajet (FO), the G6AT was engineered for drivers seeking V6 smoothness and responsive highway performance. Emissions compliance was achieved through a three‑way catalytic converter, dual oxygen sensors, and evaporative emission controls, meeting Euro 3 standards across all production years.
One documented concern is premature wear of the timing belt tensioner and idler pulleys, which may lead to belt misalignment or failure. This issue is referenced in Hyundai Technical Service Bulletin TSB‑03‑07‑004. The root cause is attributed to early‑design bearing materials with insufficient thermal fatigue resistance. From mid‑2004, Hyundai revised the pulley assembly with improved metallurgy and lubrication retention.
All production years (2002–2006) meet Euro 3 emissions standards (VCA UK Type Approval #VCA/EMS/7123).
The Hyundai G6AT is a 2,656 cc V6 naturally aspirated petrol engine engineered for mid-size models (2002–2006). It combines DOHC 24‑valve architecture with sequential multi-point fuel injection to deliver smooth mid-range power and refined idle quality. Designed to meet Euro 3 emissions standards, it balances performance with drivability in both urban and highway conditions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,656 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | V6, DOHC, 24‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 76.0 mm | |
| Power output | 125 kW (170 PS) @ 5,500 rpm | |
| Torque | 245 Nm @ 4,000 rpm | |
| Fuel system | Sequential multi‑point fuel injection (SFI) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 9.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt‑driven (DOHC, dual camshafts per bank) | |
| Oil type | API SH/SJ, SAE 10W‑30 or 10W‑40 | |
| Dry weight | 168 kg |
The DOHC V6 layout provides smooth power delivery but requires strict adherence to 60,000 km timing belt replacement to prevent interference damage. Use of API SH/SJ 10W‑30 oil is essential for camshaft and tensioner longevity, especially under high-load conditions. Early tensioner pulleys (pre‑06/2004) are prone to bearing wear; replacement with the updated assembly per TSB‑03‑07‑004 is recommended during belt service. The SFI system tolerates standard unleaded fuel but benefits from periodic injector cleaning to maintain balance across all six cylinders.
Oil Specs: Requires API SH/SJ (or equivalent) 10W‑30/10W‑40 (Hyundai Owner’s Manual 2003). ACEA A3 acceptable.
Emissions: Euro 3 certification applies to all 2002–2006 G6AT engines (VCA Type Approval #VCA/EMS/7123). No market variations.
Power Ratings: Measured under SAE J1349 standards. Output verified on chassis dyno per Hyundai PT‑2003.
Hyundai Technical Information System (TIS): Docs H‑02187, H‑03215
Hyundai Technical Service Bulletin TSB‑03‑07‑004
VCA Type Approval Database (VCA/EMS/7123)
SAE International: J1349 Engine Power Certification Standards
The Hyundai G6AT was used across Hyundai's NF, SM, and FO platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Sonata sedan and modified accessory brackets in the Santa Fe—and from 2005 the facelifted Trajet adopted updated ECU calibrations for improved cold-start emissions, creating minor ECU interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the left cylinder bank near the timing cover (Hyundai TIS H‑02187). The 4th and 5th digits of the VIN indicate engine type ('AT' for G6AT). Early models (2002–2003) use black plastic cam covers with '2.7 V6' embossed; later units (2004–2006) feature silver covers. Critical differentiation from G6CU: G6AT uses belt-driven DOHC; G6CU is chain-driven. ECU part numbers must match production date—pre‑2005 ECUs lack updated cold-start logic (Hyundai TSB‑05‑01‑006).
The G6AT's primary reliability risk is timing belt tensioner and idler pulley wear on early builds, with elevated incidence in high‑temperature or high‑load usage. Hyundai internal service data from 2004 noted pulley bearing failures in ~8% of pre‑2004 engines before 75,000 km, while UK DVSA MOT records show timing-related faults were rare but catastrophic when they occurred. Extended service intervals and use of non‑spec oil accelerate wear, making timely belt service critical.
Analysis derived from Hyundai technical bulletins (2003–2006) and UK DVSA failure statistics (2006–2016). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HYUNDAI G6AT.
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Regulation (EC) No 715/2007
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