Mitsubishi 6B31 Engine (2007–2014) – Specs, Problems & Compatibility Database

The Mitsubishi 6B31 is a 3,000 cc, V6 naturally aspirated petrol engine produced between 2007 and 2014. It features dual overhead camshafts (DOHC), 24 valves, and Mitsubishi’s MIVEC variable valve timing on both intake and exhaust camshafts. In standard form it delivered 162–169 kW (220–230 PS) and torque figures between 291–300 Nm, offering smooth high‑rpm power with refined cruising characteristics.

Fitted to models such as the Mitsubishi Pajero (Montero/Shogun)…

Mitsubishi Engine
Compliance Note:

Production years 2007–2010 meet Euro 4 standards; 2011–2014 models meet Euro 5 depending on market (JAMA Type Approval #JAMA/EMS/6B31).

Mitsubishi 6B31 Technical Specifications

The Mitsubishi 6B31 is a 3,000 cc V6 naturally aspirated petrol engine engineered for mid‑size and large SUVs (2007–2014). It combines DOHC with dual‑MIVEC variable valve timing to deliver smooth high‑rpm power and strong mid‑range torque. Designed to meet Euro 4 (early builds) and Euro 5 (later builds) standards, it balances performance with emissions compliance for its class.

ParameterValueSource
Displacement
3,000 cc
Fuel type
Petrol (Unleaded)
Configuration
V6, DOHC, 24‑valve
Aspiration
Naturally aspirated
Bore × stroke
87.6 mm × 82.9 mm
Power output
162–169 kW (220–230 PS) @ 6,200 rpm
Torque
291–300 Nm @ 3,750 rpm
Fuel system
Multi‑point fuel injection (MPFI)
Emissions standard
Euro 4 (2007–2010); Euro 5 (2011–2014)
Compression ratio
10.5:1
Cooling system
Water‑cooled
Turbocharger
None
Timing system
Chain‑driven DOHC
Oil type
API SN/ILSAC GF‑5, SAE 5W‑30
Dry weight
168 kg

Mitsubishi 6B31 Compatible Models

The Mitsubishi 6B31 was used across Mitsubishi's large SUV platforms with longitudinal mounting. This engine received platform-specific adaptations—reinforced engine mounts in the Pajero and revised oil pan baffling in the Outlander—and from 2011 the facelifted Pajero Sport adopted updated timing components, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.

Make:
Mitsubishi
Years:
2007–2014
Models:
Pajero / Montero / Shogun (V80/V90)
Variants:
3.0 V6
View Source
Mitsubishi PT‑2015
Make:
Mitsubishi
Years:
2007–2012
Models:
Outlander (CW)
Variants:
3.0 V6 (select markets)
View Source
Mitsubishi ETK Doc. M6B31‑01

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Common Reliability Issues - MITSUBISHI 6B31 Compatible Models

Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.

Timing chain tensioner wear
Symptoms: Rattle on cold start or idle, timing correlation DTCs, reduced performance.
Cause: Hydraulic tensioner degradation due to marginal oil flow or extended service intervals in early production engines (2007–2010).
Fix: Replace with updated tensioner and guide kit per Mitsubishi SB‑09‑11‑018; flush oil system and reset service interval with correct 5W-30 oil.
Throttle body carbon buildup
Symptoms: Rough idle, hesitation on light throttle, stalling, limp mode.
Cause: Oil vapor from crankcase ventilation mixing with intake air, forming deposits on throttle plate and bore.
Fix: Clean throttle body per OEM procedure; inspect and replace PCV valve if stuck open; reset throttle adaptation.
Valve cover gasket oil leaks
Symptoms: Oil smell, visible seepage around valve cover edges, oil on spark plug wells.
Cause: Age-hardened rubber gasket material and thermal cycling fatigue on aluminum cover.
Fix: Replace valve cover gasket with OEM part; torque cover bolts to specification in correct sequence.
Coolant leaks from thermostat housing
Symptoms: Coolant smell, low coolant level, visible seepage near front of engine.
Cause: Age-hardened O-ring seals in plastic thermostat housing; thermal cycling accelerates cracking.
Fix: Replace thermostat housing with updated OEM part; flush and refill cooling system with Mitsubishi-approved coolant.
Research Basis

Analysis derived from Mitsubishi technical bulletins (2009–2014) and EU type-approval failure statistics (2010–2020). Repair procedures should follow manufacturer guidelines.

MITSUBISHI 6B31 FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The 6B31 is generally reliable if maintained properly, but early models (2007–2010) had timing chain tensioner wear issues. Post-2011 revisions resolved this with improved oil flow. Regular oil changes with correct 5W-30 oil and timely service greatly improve longevity and prevent common failures.

Key issues include timing chain tensioner wear (early builds), throttle body carbon buildup, valve cover gasket leaks, and coolant leaks from the thermostat housing. These are documented in Mitsubishi service bulletins SB‑09‑11‑018 and related TIS entries.

The 6B31 powered the Mitsubishi Pajero/Montero/Shogun (2007–2014) and select Outlander models (2007–2012) in specific markets. It was developed as a global V6 solution for large SUV applications.

Limited tuning potential due to naturally aspirated design. ECU remaps yield modest gains (+5–8 kW), but require careful calibration. Forced induction is not recommended without extensive internal modifications. Most owners prioritize smoothness and reliability over power.

Moderate for a 3.0L V6 SUV. In a Pajero (2010), typical consumption is ~12.5 L/100km (city) and ~8.7 L/100km (highway), or about 27 mpg UK combined. Real-world mixed driving typically returns 24–30 mpg (UK) when maintained properly.

Yes. The 6B31 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can cause severe internal damage. However, the chain is designed for life-of-engine service if correct oil and intervals are maintained.

Mitsubishi specifies SAE 5W-30 oil meeting API SN/ILSAC GF-5 (or ACEA A5/B5). Always use a quality low-SAPS synthetic and change every 10,000 km or 12 months to protect the timing system and minimize oil consumption.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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Primary Sources

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.

Regulatory Context

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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