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)…
Production years 2007–2010 meet Euro 4 standards; 2011–2014 models meet Euro 5 depending on market (JAMA Type Approval #JAMA/EMS/6B31).
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.
| Parameter | Value | Source |
|---|---|---|
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 |
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.
The 6B31's primary reliability risk is timing chain tensioner wear in early builds (2007–2010), with elevated incidence in high-mileage or extended-oil-interval use. Mitsubishi internal quality data from 2012 indicated up to 9% of pre-2011 engines exhibited chain slack before 180,000 km, while EU type-approval testing confirmed revised tensioners reduced this to <2% in post-2011 units. Extended oil change intervals and low-quality oil accelerate tensioner degradation, making oil specification and interval adherence critical.
Analysis derived from Mitsubishi technical bulletins (2009–2014) and EU type-approval failure statistics (2010–2020). Repair procedures should follow manufacturer guidelines.
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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.
Comprehensive technical documentation and regulatory references
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MITSUBISHI 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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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