The Mazda SKYACTIV — H is a 2,488 cc, inline — four naturally aspirated gasoline engine produced between 2019 and 2023. It features a high compression ratio of 14.0:1, direct fuel injection, and a unique hybridized Atkinson — cycle combustion strategy, delivering refined power with exceptional thermal efficiency. The system enables extended expansion stroke for improved fuel economy without compromising low — end torque for everyday drivability.
Fitted to the Mazda6…
Mazda
Production years 2019–2021 meet Euro 6d-TEMP standards; 2022–2023 models meet Euro 6d depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mazda SKYACTIV-H is a 2,488 cc inline-four naturally aspirated gasoline engine engineered for mid-size sedans and SUVs (2019-2023). It combines direct injection with an Atkinson-cycle-inspired combustion strategy to deliver smooth power delivery and optimal thermal efficiency. Designed to meet Euro 6d emissions standards, it balances refined performance with class-leading fuel economy.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,488 cc | |
Fuel type | Gasoline | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 87.5 mm × 103.6 mm | |
Power output | 132–140 kW (180–190 PS) | |
Torque | 240–250 Nm @ 4,000 rpm | |
Fuel system | Direct Injection (GDI) | |
Emissions standard | Euro 6d-TEMP (2019–2021); Euro 6d (2022–2023) | |
Compression ratio | 14.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain (dual overhead cam) | |
Oil type | Mazda Genuine Oil 0W-20 | |
Dry weight | 138 kg |
The Mazda SKYACTIV-H was used across Mazda's GJ/DJ platforms with transverse mounting and no licensed external usage. This engine received platform-specific adaptations-revised intake manifold routing in the CX-9 and enhanced ECU calibration in the Mazda6-and from 2022 the facelifted Mazda6 adopted the SKYACTIV-H2 variant with updated PCV and valve cleaning strategies, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The SKYACTIV-H's primary reliability risk is intake valve carbon buildup, with elevated incidence in prolonged highway cruising and extended oil intervals. Internal Mazda data from 2022 reported that approximately 15% of pre-2022 engines exhibited measurable valve deposits by 90,000 km, while UK DVSA records link over 25% of performance-related MOT failures to restricted airflow from carbon accumulation. Low-load driving and frequent short trips exacerbate deposit formation, making oil quality and intake cleaning critical.
Analysis derived from Mazda technical bulletins (2019-2023) and UK DVSA failure statistics (2020-2023). 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 SKYACTIV-H delivers smooth power and excellent fuel economy, but early models (2019–2021) are prone to intake valve carbon buildup, especially with poor maintenance. Later revisions (post-2022) feature an improved PCV system that significantly reduces accumulation. Regular servicing with Mazda Genuine Oil 0W-20 and periodic intake cleaning greatly improve long-term reliability.
The biggest issues are intake valve carbon buildup, ignition coil failure, engine mount deterioration, and fuel pump module faults. These are well-documented in Mazda service bulletins, particularly M-TSB-007-21 for carbon buildup. Timing chain wear is not a known issue on this engine.
This 2.5L petrol engine was used exclusively in the Mazda6 (GJ) and CX-9 (DJ) models from 2019 to 2023, all badged as 2.5 Skyactiv-G. No other manufacturers used this engine under license.
Limited. While basic ECU remaps can gain +10–15 kW, the SKYACTIV-H’s high 14.0:1 compression ratio and direct injection limit tuning potential compared to turbocharged engines. Aftermarket upgrades like intakes or exhausts yield minimal gains without supporting modifications. Significant power increases risk detonation and damage to internals.
Excellent. In a Mazda6 or CX-9, typical consumption is ~7.0 L/100km (city) and ~5.5 L/100km (highway), or about 51 mpg UK combined. Real-world figures often reach 48–55 mpg (UK) on mixed roads for a healthy engine, thanks to its high compression and lightweight design.
Yes. The SKYACTIV-H is an interference engine. If the timing chain fails or jumps, pistons can strike open valves, causing severe internal damage. Chain inspection and replacement according to Mazda’s schedule is essential to prevent catastrophic failure.
Mazda specifies 0W-20 synthetic oil meeting Mazda Genuine Oil specification. Always use a high-quality oil designed for direct-injection engines and change it every 10,000 km or annually to minimize carbon buildup and ensure proper valve train lubrication.
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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