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 (GJ) and CX-9 (DJ) models as the standard powertrain, the SKYACTIV-H was engineered for drivers seeking quiet operation, smooth acceleration, and superior long-distance fuel economy. Emissions compliance was achieved through exhaust gas recirculation (EGR), a three-way catalytic converter, and precise air-fuel control, allowing all units to meet Euro 6d-TEMP and Euro 6d standards across European markets.
One documented concern is carbon accumulation on intake valves under prolonged low-load conditions; this issue, highlighted in Mazda Technical Service Bulletin M-TSB-007-21, stems from oil vapors from the PCV system depositing on valve surfaces during frequent highway cruising. Mazda introduced revised PCV valve design and updated ECU calibration in late 2020 to reduce vapor flow and mitigate buildup rates.
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 SKYACTIV-H's high-compression Atkinson cycle delivers excellent fuel economy but requires strict adherence to 10,000 km oil change intervals using Mazda Genuine Oil 0W-20 to prevent intake valve carbon buildup. Low-viscosity oil is critical due to its ability to flow through narrow passages in the cylinder head and reduce deposit formation. Extended highway cruising at low loads accelerates carbon accumulation; periodic use of injector cleaner and intake cleaning procedures per Mazda SIB M-TSB-007-21 are recommended. Use of ultra-low-sulfur gasoline meeting EN 228 standards is mandatory to protect the catalytic converter and ensure emissions compliance.
Oil Specs: Requires Mazda Genuine Oil 0W-20 specification (Mazda SIB M-TSB-007-21). Supersedes ACEA C5 requirements.
Emissions: Euro 6d-TEMP certification applies to 2019–2021 models only (VCA Type Approval #VCA/EMS/5678). Euro 6d applies to 2022–2023 models depending on market.
Power Ratings: Measured under SAE J1349 standards. 140 kW output requires EU3+ fuel quality (Mazda TIS Doc. A79020).
Mazda Technical Information System (TIS): Docs A78925, A79020, SIB M-TSB-007-21
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine code stamped on the front right side of the cylinder block near the oil filter housing (Mazda TIS A78925). The 7th VIN digit indicates engine family ('H' for SKYACTIV-H series). Pre-2022 models have silver valve covers with black plastic timing covers; post-2022 units use matte-black valve covers. Critical differentiation from SKYACTIV-H2: Original SKYACTIV-H has a single-stage PCV valve; SKYACTIV-H2 uses a two-stage valve with internal baffles. Service parts require production date verification - intake cleaning kits for pre-2022 engines are incompatible with later units due to revised valve guide geometry (Mazda SIB M-TSB-007-21).
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.
Find answers to most commonly asked questions about MAZDA SKYACTIV-H.
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