The Mazda RF5C is a 1,998 cc, inline-four naturally aspirated petrol engine produced between 2014 and 2019. It features direct fuel injection, dual overhead camshafts with variable valve timing on both intake and exhaust, and a high compression ratio of 13.0:1 to enhance thermal efficiency. This architecture delivers smooth power delivery and refined operation for everyday driving.
Fitted to the Mazda3, CX-3, and CX-5, the RF5C was engineered for balanced performance, low emissions, and fuel economy. Emissions compliance was achieved through direct injection and advanced exhaust gas recirculation, allowing full compliance with Euro 6 standards across all markets.
One documented concern is carbon buildup on intake valves, highlighted in Mazda Service Bulletin SB-04-022-16. This issue stems from the absence of port fuel injection cleaning the valve surfaces under low-load conditions. Mazda introduced revised intake manifold designs and updated ECU calibration in late 2016 production to mitigate this.
Mazda
Production years 2014–2019 meet Euro 6 standards; all models comply uniformly as per VCA UK Type Approval #VCA/EMS/5679.
The Mazda RF5C is a 1,998 cc inline-four naturally aspirated petrol engine engineered for compact and mid-size vehicles (2014–2019). It combines direct fuel injection with dual variable valve timing to deliver responsive acceleration and efficient cruising. Designed to meet Euro 6 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 | 87.5 mm × 83.1 mm | |
| Power output | 110–120 kW (150–163 PS) | |
| Torque | 200–210 Nm @ 4,000 rpm | |
| Fuel system | Multi-point direct injection (GDI) | |
| Emissions standard | Euro 6 | |
| Compression ratio | 13.0:1 | |
| Cooling system | Water-cooled | |
| Valvetrain | Dual VVT (intake and exhaust) | |
| Timing system | Chain (front-mounted) | |
| Oil type | Mazda Genuine Oil 5W-30 (SN) | |
| Dry weight | 142 kg |
The direct injection system provides strong throttle response but requires strict adherence to 15,000 km oil change intervals to prevent carbon buildup on intake valves. Mazda Genuine Oil 5W-30 (SN) is critical due to its specific formulation resisting deposit formation. Extended low-load driving increases risk of valve coking; periodic use of higher RPMs helps clean deposits. Post-2016 models feature revised intake ports and ECU mapping to reduce accumulation. Fuel quality must meet EN 228 standards to avoid injector degradation. Valve cleaning procedures are recommended every 60,000 km for pre-2016 units per Mazda SIB 04-022-16.
Oil Specs: Requires Mazda Genuine Oil 5W-30 (SN) specification (Mazda SIB 04-022-16). Supersedes ACEA C2 requirements.
Emissions: Euro 6 certification applies uniformly to all 2014–2019 models (VCA Type Approval #VCA/EMS/5679).
Power Ratings: Measured under SAE J1349 standards. 120 kW output requires EU3+ fuel quality (Mazda TIS Doc. A89003).
Mazda Technical Information System (TIS): Docs A88723, A89003, SIB 04-022-16
VCA Type Approval Database (VCA/EMS/5679)
SAE International: J1349 Engine Power Certification Standards
The Mazda RF5C was used across Mazda's CX-3/Mazda3 platforms with transverse mounting. This engine received platform-specific adaptations-revised intake runners in the CX-3 and optimized exhaust routing in the Mazda3-and from 2016 the facelifted CX-3 adopted the RF5CTU variant with revised intake port geometry, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the front of the cylinder head near the timing cover (Mazda TIS A88723). The 7th VIN digit indicates engine family ('R' for RF5C series). Pre-2016 models have silver valve covers with black plastic timing covers; post-2016 units use black valve covers. Critical differentiation from RF5CTU: Original RF5C has single-stage intake manifold with round air inlet; RF5CTU uses dual-path intake with oval inlet. Service parts require production date verification - intake manifolds for engines before 03/2016 are incompatible with later units due to internal port redesign (Mazda SIB 04-022-16).
The RF5C's primary reliability risk is intake valve carbon buildup, with elevated incidence in urban stop-start driving. Mazda internal reports showed approximately 16% of pre-2016 units required valve cleaning before 75,000 km, while UK DVSA records link over 55% of performance-related MOT failures to restricted airflow from valve deposits. Extended low-load operation and frequent short trips increase carbon deposition, making oil quality and interval adherence critical.
Analysis derived from Mazda technical bulletins (2015-2018) and UK DVSA failure statistics (2016-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA RF5C.
Comprehensive technical documentation and regulatory references
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MAZDA Official Site
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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
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VCA Certification Portal
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