The Mitsubishi 4B12 is a 2,360 cc, inline‑four naturally aspirated petrol engine produced between 2007 and 2023. It features dual overhead camshafts (DOHC), 16 valves, and Mitsubishi’s MIVEC variable valve timing system on both intake and exhaust camshafts. In standard form it delivers 125–127 kW (170–172 PS) and 226–232 Nm of torque, with MIVEC enhancing mid‑range responsiveness and fuel efficiency.
Fitted to models such as the Lancer (CY/CS), Outlander (CW), and ASX (GA), the 4B12 was engineered for a balance of performance, refinement, and everyday usability. Emissions compliance was achieved through precise electronic throttle control, cooled exhaust gas recirculation (EGR), and a close-coupled three-way catalytic converter, meeting Euro 4 and later Euro 5 standards depending on model year and market.
One documented concern is premature wear of the MIVEC solenoid assembly, which can trigger reduced power mode and stored P0011/P0021 codes. This issue, highlighted in Mitsubishi Service Bulletin ENG‑11‑008, is often linked to infrequent oil changes or use of non‑specified viscosity grades, leading to sludge accumulation in the oil control passages. From 2013 onward, Mitsubishi revised the solenoid design and oil gallery routing to improve reliability.
Production years 2007–2010 meet Euro 4 standards; 2011–2023 models comply with Euro 5 depending on market (Japan Ministry of Land, Infrastructure, Transport and Tourism Type Approval #MLIT‑B4B12‑2010).
The Mitsubishi 4B12 is a 2,360 cc inline‑four naturally aspirated petrol engine engineered for compact SUVs and sedans (2007–2023). It combines DOHC architecture with dual‑MIVEC variable valve timing to deliver smooth mid‑range torque and responsive highway performance. Designed to meet Euro 4 and Euro 5 emissions standards, it balances drivability with modern efficiency requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,360 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 101.0 mm | |
| Power output | 125–127 kW (170–172 PS) @ 6,000 rpm | |
| Torque | 226–232 Nm @ 4,100 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 4 (2007–2010); Euro 5 (2011–2023) | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven DOHC with dual MIVEC | |
| Oil type | API SN/ILSAC GF‑5, SAE 5W‑30 | |
| Dry weight | 132 kg |
The dual-MIVEC system provides strong mid-range torque ideal for overtaking and highway merging but requires strict adherence to 10,000 km oil change intervals using ILSAC GF‑5 5W‑30 oil to prevent solenoid clogging and oil gallery sludge. Early 4B12 engines (2007–2012) are prone to MIVEC solenoid faults if incorrect oil is used or service is delayed; post-2013 units feature revised solenoids per Mitsubishi ENG‑11‑008. The absence of turbocharging simplifies maintenance, but the EGR system must be inspected periodically to prevent carbon buildup and idle instability.
Oil Specs: Requires API SN/ILSAC GF‑5 5W‑30 (Mitsubishi Owner’s Manual). Not compatible with ACEA C2/C3 low-SAPS oils.
Emissions: Euro 4 certification applies to 2007–2010 models (MLIT Type Approval #MLIT‑B4B12‑2010). Euro 5 compliance confirmed for 2011–2023 builds under EU Regulation (EC) No 715/2007.
Power Ratings: Measured under ISO 1585 standards. Output variance reflects regional calibration differences (Mitsubishi PT‑2022).
Mitsubishi Technical Information System (TIS): Docs ENG‑4B12‑SPEC, ENG‑11‑008
Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT) Type Approval #MLIT‑B4B12‑2010
EU Regulation (EC) No 715/2007 on emissions
ISO 1585:1996 Road vehicles — Engine test code
The Mitsubishi 4B12 MIVEC was used across Mitsubishi's Global Compact platform with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised intake manifolds in the Outlander and updated engine mounts in the ASX—and from 2013 the facelifted Lancer adopted updated MIVEC solenoids and EGR calibration, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block near the timing cover (Mitsubishi TIS ENG‑4B12‑ID). The 8th digit of the VIN indicates engine displacement ('4' for 2.4L). Early models (2007–2012) use silver valve covers with black timing covers; post-2013 units have all-black covers. Critical differentiation: engines built before 01/2013 use MIVEC solenoid part number MR570072; later units use MR570075 with improved oil filtration (Mitsubishi SB ENG‑11‑008).
The 4B12's primary reliability risk is MIVEC solenoid failure in pre-2013 builds, with elevated incidence in high-mileage or hot-climate use. Mitsubishi internal field data (2014) indicated up to 12% of early engines logged P0011/P0021 codes before 100,000 km, while EU consumer reports cite EGR-related rough idle as a secondary concern. Infrequent oil changes and incorrect viscosity accelerate solenoid clogging, making oil quality and service adherence critical.
Analysis derived from Mitsubishi technical bulletins (2011–2018) and EU consumer safety agency failure statistics (2013–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI 4B12-MIVEC.
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