The Hyundai G6CT is a 2,656 cc, V6 naturally aspirated petrol engine produced between 2005 and 2010. It features a dual overhead camshaft (DOHC) layout with 24 valves and Hyundai’s Variable Intake System (VIS) for optimized airflow. In standard form it delivered 125–132 kW (170–180 PS) and torque figures between 245–255 Nm, providing smooth power delivery and refined highway cruising.
Fitted to models such as the Grandeur TG, Sonata NF, and Azera TG, including the 2.7 V6 G…
Hyundai
All production years 2005–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/6543).
The Hyundai G6CT is a 2,656 cc V6 naturally aspirated petrol engine engineered for mid-size sedans (2005–2010). It combines DOHC architecture with a Variable Intake System (VIS) to enhance mid-range torque and acoustic refinement. Designed to meet Euro 4 emissions standards, it balances smooth power delivery with long-term drivability and serviceability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,656 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | V6, DOHC, 24‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 83.0 mm × 82.0 mm | |
Power output | 125–132 kW (170–180 PS) @ 6,000 rpm | |
Torque | 245–255 Nm @ 4,000 rpm | |
Fuel system | Sequential multi-point fuel injection (SFI) | |
Emissions standard | Euro 4 | |
Compression ratio | 10.4:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain (dual chains, maintenance-free design) | |
Oil type | Hyundai SP 5W‑30 (API SL/SM) | |
Dry weight | 168 kg |
The Hyundai G6CT was used across Hyundai's TG/NF platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—reinforced mounts in the Grandeur TG and revised intake manifolds in the Sonata NF—and from 2008 the updated HLA design improved cold-start quietness, creating minor ECU and parts interchange limits. All adaptations are documented in OEM technical bulletins.
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The G6CT's primary reliability risk is hydraulic lash adjuster (HLA) wear, with elevated incidence in high-mileage or poorly maintained engines. Hyundai internal data from 2009 indicated a notable share of 2005–2007 engines exhibiting valve train noise before 120,000 km, while UK DVSA records show few emissions-related failures due to robust catalytic design. Extended oil change intervals and urban driving increase HLA clogging risk, making oil quality and interval adherence critical.
Analysis derived from Hyundai technical bulletins (2007–2011) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The G6CT is generally smooth and durable with disciplined maintenance. Early models (2005–2007) are prone to HLA noise if oil changes are delayed, but post-2008 revisions improved reliability. Using correct 5W-30 oil and adhering to 10,000 km service intervals ensures longevity beyond 200,000 km.
Top issues include hydraulic lash adjuster wear, VIS actuator faults, valve cover oil leaks, and plastic thermostat housing cracks. These are documented in Hyundai service bulletins HMC-SB-07-018 and TIS updates. Most are preventable with proper oil and coolant maintenance.
The G6CT powered the Grandeur TG (2005–2010), Sonata NF (2005–2010), and Azera TG (2006–2010) in 2.7 V6 petrol variants. It was not used in later generations or licensed to other manufacturers. All applications are longitudinally mounted and Euro 4 compliant.
Limited tuning potential. Stage 1 ECU remaps yield modest gains (+8–12 kW) due to conservative factory calibration. Forced induction is not recommended—stock internals lack strength for significant boost. Focus on cold air intake and cat-back exhaust for improved response.
In a Sonata 2.7 V6 Limited, expect ~11.5 L/100km (city) and ~7.2 L/100km (highway), or ~28 mpg UK combined. Real-world economy depends heavily on driving style and maintenance condition.
Yes. The G6CT is an interference engine. If either timing chain were to fail, pistons will contact open valves, causing severe internal damage. However, chain failures are extremely rare due to robust design and oil pressure monitoring.
Hyundai specifies 5W-30 synthetic or semi-synthetic oil meeting Hyundai SP or ACEA A3/B4 standards. Change every 10,000 km or 12 months. Avoid low-SAPS or C3 oils—they lack the detergency needed for HLA cleanliness.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
HYUNDAI Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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