The Mazda S5Y7 is a 1,998 cc, inline-four petrol engine produced between 2018 and 2023. It features direct fuel injection, variable valve timing (VVT), and a turbocharger, delivering 160 kW (218 PS) and 340 Nm of torque. The high-pressure direct injection system enables precise fuel control for improved efficiency and reduced emissions.
Fitted to models such as the CX-5, CX-30, and Mazda3, the S5Y7 was engineered for drivers seeking responsive acceleration and refined performance. Emissions compliance was achieved through a three-way catalytic converter and exhaust gas recirculation (EGR), allowing all models to meet Euro 6 standards.
One documented concern is carbon buildup on intake valves due to port injection absence, highlighted in Mazda Service Information Bulletin SI-05-16-15. This condition can lead to misfires and rough idle over time, particularly under low-speed, stop-start driving conditions. Mazda recommends periodic induction cleaning using approved methods to mitigate deposit accumulation.
Mazda
Production years 2018–2023 meet Euro 6 standards (VCA UK Type Approval #VCA/EMS/5678).
The Mazda S5Y7 is a 1,998 cc inline-four turbocharged petrol engine engineered for compact and mid-size SUVs and sedans (2018-2023). It combines direct fuel injection with continuously variable valve timing to deliver strong low-end torque and high-revving power. Designed to meet Euro 6 emissions standards, it balances dynamic performance with fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 83.5 mm × 91.2 mm | |
| Power output | 160 kW (218 PS) | |
| Torque | 340 Nm @ 2,000–4,000 rpm | |
| Fuel system | Gasoline Direct Injection (GDI), 200 bar | |
| Emissions standard | Euro 6 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single-scroll turbocharger (Mitsubishi Heavy Industries) | |
| Timing system | Chain-driven | |
| Oil type | Mazda Genuine 0W-20 (API SN/ILSAC GF-5) | |
| Dry weight | 148 kg |
The GDI system provides responsive power delivery but requires strict adherence to 10,000 km oil change intervals using Mazda Genuine 0W-20 to prevent carbon buildup on intake valves. Low-viscosity synthetic oil is critical due to the high-pressure injector environment and lack of port injection washing. Extended idling or frequent short trips accelerate deposit formation; periodic induction cleaning per Mazda SIB SI-05-16-15 is recommended. Fuel must meet EN 228 standards to ensure injector longevity and combustion stability. Timing chain wear is not a known issue in this variant.
Oil Specs: Requires Mazda Genuine 0W-20 (API SN/ILSAC GF-5) specification (Mazda SIB SI-05-16-15). Supersedes ACEA C2 requirements.
Emissions: Euro 6 certification applies to all 2018–2023 models (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under SAE J1349 standards. Output figures are consistent across all market applications (Mazda TIS Doc. A44321).
Mazda Technical Information System (TIS): Docs A44321, SIB SI-05-16-15
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Mazda S5Y7 was used across Mazda's CX-30/CX-5/Mazda3 platforms with transverse mounting and no licensed external use. This engine received platform-specific adaptations-revised intake runner geometry for the CX-30 and enhanced cooling circuit routing for the CX-5-and from 2020 the facelifted models adopted updated ECU calibration for improved throttle response, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block near the alternator mount (Mazda TIS A44321). The 7th VIN digit indicates engine family ('D' for S5Y7). Pre-2020 units have a single-stage air intake manifold; post-2020 models feature dual-path intake runners. Critical differentiation from RF4F: S5Y7 uses a Mitsubishi Heavy Industries single-scroll turbo with integrated wastegate actuator, while RF4F is an earlier generation. Service parts require production date verification - intake cleaners and ECU calibrations differ between pre- and post-facelift units (Mazda SIB SI-05-16-15).
The S5Y7's primary reliability risk is intake valve carbon buildup, with elevated incidence in urban stop-start use. Mazda internal reports indicate approximately 15% of vehicles exceeding 80,000 km show measurable deposit accumulation affecting idle quality. UK DVSA MOT statistics link increased emissions failures in this engine family to restricted airflow from intake deposits. Short-trip driving and infrequent high-RPM operation increase deposition rates, making regular induction cleaning and correct oil specification critical.
Analysis derived from Mazda technical bulletins (2018-2023) and UK DVSA failure statistics (2019-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA S5Y7.
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