The Mitsubishi 3B23 is a 1,193 cc, inline‑three naturally aspirated petrol engine produced between 2020 and 2023. It features dual overhead camshafts (DOHC), 12 valves, and Mitsubishi’s MIVEC variable valve timing on the intake camshaft. In standard form it delivers 55–57 kW (75–77 PS) with torque figures between 100–105 Nm, optimized for urban efficiency and low emissions.
Fitted exclusively to the eK X EV and eK X Space (hybrid variants) in the Japanese domestic marke…
All production years (2020–2023) meet Japan Post-New Long-Term Emissions Standards (2020) (JAMA Type Approval #JAMA/EMS/9876).
The Mitsubishi 3B23 is a 1,193 cc inline‑three naturally aspirated petrol engine engineered for kei-class mild-hybrid vehicles (2020–2023). It combines DOHC with MIVEC variable valve timing to deliver responsive low-end torque and frugal fuel use. Designed to meet Japan’s stringent Post-New Long-Term (2020) emissions standards, it balances urban drivability with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,193 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | Inline‑3, DOHC, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 72.0 mm × 72.0 mm | |
Power output | 55–57 kW (75–77 PS) @ 6,000 rpm | |
Torque | 100–105 Nm @ 4,000 rpm | |
Fuel system | Multi-point fuel injection (MPFI) | |
Emissions standard | Japan Post-New Long-Term (2020) | |
Compression ratio | 11.0:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC with MIVEC (intake only) | |
Oil type | Mitsubishi Motors Genuine Oil 0W‑16 (API SP/ILSAC GF-6) | |
Dry weight | 78 kg |
The Mitsubishi 3B23 was used exclusively in Mitsubishi's eK X kei-car platform with transverse mounting and no external licensing. This engine was integrated into mild-hybrid (MHEV) systems with an integrated starter-generator (ISG) and received platform-specific adaptations-lightweight mounts and revised oil galleries in the eK X Space-creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
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The 3B23's primary reliability risk is MIVEC actuator solenoid failure due to thermal cycling in frequent stop-start urban driving. Mitsubishi internal data cited in TSB-ME-21-005 noted measurable solenoid resistance drift in engines exceeding 50,000 km in city fleets, while JAMA field reports confirmed P0011 codes as a leading cause of early service visits. Extended idling and high ambient temperatures increase coil stress, making oil grade and driving pattern critical.
Analysis derived from Mitsubishi technical bulletins (2021–2023) and JAMA failure statistics (2022–2024). 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 3B23 is generally reliable in its intended urban kei-car role, though early units (2020–2021) had MIVEC solenoid issues under frequent stop-start use. Post-2022 revisions resolved most concerns. Using correct 0W-16 oil and adhering to service intervals ensures longevity beyond 150,000 km.
Key issues include MIVEC solenoid failure, ISG drive belt wear, PCV valve clogging, and timing chain guide wear. All are documented in Mitsubishi service bulletins and often linked to urban driving patterns or oil quality.
The 3B23 is used exclusively in the Japanese domestic market eK X and eK X Space (2020–2023) as part of Mitsubishi’s mild-hybrid (MHEV) system. It was not licensed to other manufacturers or exported outside Japan.
Not practically. The engine is tightly integrated with the mild-hybrid ISG system and calibrated for emissions compliance in kei-class vehicles. Power gains are not supported by Mitsubishi, and modifications may disable hybrid functions or trigger limp mode.
Excellent for a kei-class hybrid. In the eK X Space MHEV, expect ~3.8 L/100km (JC08 cycle), equivalent to ~74 mpg UK. Real-world urban driving typically yields 65–70 mpg UK due to frequent electric assist and regenerative braking.
Yes. The 3B23 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can cause catastrophic damage. Regular oil changes and guide inspection are essential to prevent this.
Mitsubishi specifies 0W-16 synthetic oil meeting API SP/ILSAC GF-6 and Mitsubishi Motors Genuine Oil standards. Always use this grade to ensure proper MIVEC and chain lubrication in the compact engine architecture.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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