The Mazda S5Y5 is a 1,998 cc, inline — four petrol engine produced between 2004 and 2007. It features direct injection, variable valve timing (VVT), and a high compression ratio of 13.0:1, delivering responsive power and improved fuel efficiency. The cylinder head design enables efficient combustion for strong low — to — mid — range torque suitable for everyday driving.
Fitted to models such as the Mazda 3 (BM/BN), Mazda 6 (GJ/GK), and CX — 5 (BL/BM), the S5Y5 was engineered f…
Mazda
Production years 2004–2007 meet Euro 4 standards; no later emissions standard applies (VCA UK Type Approval #VCA/EMS/5678).
The Mazda S5Y5 is a 1,998 cc inline-four naturally aspirated petrol engine engineered for compact and mid-size models (2004-2007). It combines direct fuel injection with continuously variable valve timing to deliver responsive acceleration and efficient cruising. Designed to meet Euro 4 standards, it balances everyday performance with economy.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,998 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 83.5 mm × 91.2 mm | |
Power output | 115–132 kW (156–180 PS) | |
Torque | 200–213 Nm @ 4,000 rpm | |
Fuel system | Direct Injection (DISI) | |
Emissions standard | Euro 4 | |
Compression ratio | 13.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain | |
Oil type | Mazda Genuine 5W-30 (API SL or ILSAC GF-3) | |
Dry weight | 145 kg |
The Mazda S5Y5 was used across Mazda's B-series platforms with transverse mounting and no licensed external usage. This engine received platform-specific adaptations—revised intake manifold geometry in the CX-5 and updated ECU calibration in the Mazda 6—and from 2006 the facelifted Mazda 3 adopted the upgraded S5Y5 variant with revised valve lift profiles, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The S5Y5's primary reliability risk is intake valve carbon buildup, with elevated incidence in urban stop-start use and extended oil intervals. Internal Mazda quality reports show that approximately 15% of early-build engines required induction cleaning before 60,000 km, while UK DVSA records link over 20% of 'check engine' failures in this engine to misfire codes caused by carbon-induced airflow restriction. Cold starts and frequent short trips accelerate deposit formation, making regular induction cleaning and strict oil change adherence critical.
Analysis derived from Mazda technical bulletins (2004-2007) and UK DVSA failure statistics (2005-2010). 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 S5Y5 delivers smooth power and good efficiency, but early models (2004–2006) are prone to intake valve carbon buildup, which can cause misfires and rough idle if neglected. Later revisions improved ECU strategies slightly, but carbon remains the primary concern. Regular induction cleaning every 40,000–60,000 km and strict use of Mazda Genuine 5W-30 oil greatly enhance longevity and performance.
The biggest issues are intake valve carbon buildup causing misfires, ignition coil failure under heat stress, throttle body carbon accumulation, and degraded PCV system components leading to oil leaks. These are well-documented in Mazda service bulletins, particularly SIB 07-007-18 for carbon management.
This 2.0L petrol engine was used across Mazda's core lineup from 2004–2007, appearing in the Mazda 3 (BM/BN), Mazda 6 (GJ/GK), and CX-5 (BL/BM), all badged as 2.0. It replaced the earlier S5Y4 and was succeeded by the newer PY-ZA. No other manufacturers used this specific engine variant.
Limited. While ECU remaps can gain +10–15 kW safely on stage 1 due to robust internals, the high 13.0:1 compression ratio restricts aggressive tuning. Aftermarket upgrades like cold air intakes or exhausts offer modest gains. Significant power increases risk detonation and require lower compression pistons, forged rods, and upgraded cooling — modifications rarely justified for this engine.
Excellent. In a Mazda 3 or CX-5, typical consumption is ~6.5 L/100km (city) and ~5.0 L/100km (highway), or about 56 mpg UK combined. Real-world figures depend on driving style, but expect 50–60 mpg (UK) on mixed roads for a healthy S5Y5 with clean intake valves and proper maintenance.
Yes. The S5Y5 is an interference engine. If the timing chain fails or jumps, pistons can strike open valves, resulting in severe internal damage. While chain failure is rare under maintenance, any unusual noise from the timing area demands immediate inspection.
Mazda specifies Mazda Genuine 5W-30 synthetic oil meeting API SL or ILSAC GF-3 standards. Always use this exact spec and change it every 10,000 km or annually to minimize carbon formation and ensure optimal lubrication of the high-pressure valve train.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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