The Mitsubishi 3A91 is a 1,193 cc, inline‑three naturally aspirated petrol engine produced between 2008 and 2017. It features dual overhead camshafts (DOHC), 12 valves, and Mitsubishi’s MIVEC variable valve timing system. In standard form it delivered 59–63 kW (80–86 PS) and torque figures between 106–115 Nm, offering responsive low‑end performance for city driving.
Fitted to models such as the Mitsubishi Colt, Mirage, and ASX (in select markets), the 3A91 was engineered for urban efficiency, low emissions, and compact packaging. Emissions compliance was achieved through MIVEC valve control and a close‑coupled three‑way catalytic converter, enabling Euro 4 and later Euro 5 compliance depending on model year and region.
One documented concern is excessive oil consumption in early production units (2008–2011), highlighted in Mitsubishi Service Bulletin SB‑09‑12‑003. This issue stems from suboptimal piston ring tension and oil control land design, leading to increased blow‑by. From 2012, revised piston assemblies were introduced across all applications.
Production years 2008–2010 meet Euro 4 standards; 2011–2017 models meet Euro 5 depending on market (JAMA Type Approval #JAMA/EMS/3A91).
The Mitsubishi 3A91 is a 1,193 cc inline‑three naturally aspirated petrol engine engineered for subcompact and compact models (2008–2017). It combines DOHC with MIVEC variable valve timing to deliver responsive low‑rpm performance and urban fuel efficiency. Designed to meet Euro 4 (early builds) and Euro 5 (later builds) standards, it balances light weight with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,193 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑3, DOHC, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 90.0 mm | |
| Power output | 59–63 kW (80–86 PS) @ 6,000 rpm | |
| Torque | 106–115 Nm @ 4,000 rpm | |
| Fuel system | Multi‑point fuel injection (MPFI) | |
| Emissions standard | Euro 4 (2008–2010); Euro 5 (2011–2017) | |
| 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 | 87 kg |
The MIVEC system provides responsive low-RPM torque ideal for city driving but requires adherence to 10,000 km oil change intervals to prevent piston ring coking and oil consumption. SAE 5W-30 oil meeting API SN/ILSAC GF-5 is critical due to its low-SAPS formulation protecting catalytic efficiency. Early engines (2008–2011) should be inspected for oil consumption exceeding 0.5 L/1,000 km per SB‑09‑12‑003. Post-2012 units feature revised pistons with improved oil control lands. The timing chain is maintenance-free but sensitive to oil degradation—extended intervals risk tensioner wear.
Oil Specs: Requires API SN/ILSAC GF-5 (5W-30) specification (Mitsubishi SB‑09‑12‑003). ACEA A5/B5 oils are acceptable alternatives.
Emissions: Euro 4 certification applies to 2008–2010 models only (JAMA Type Approval #JAMA/EMS/3A91). Euro 5 compliance confirmed for 2011–2017 builds.
Power Ratings: Measured under ISO 1585 standards. Power varies slightly by ECU calibration and market (Mitsubishi TIS Doc. MIVEC‑3A91).
Mitsubishi Technical Information System (TIS): Docs MIVEC‑3A91, TIMING‑3A91, FUEL‑3A91
JAMA Type Approval Database (JAMA/EMS/3A91)
ISO 1585: Road vehicles — Engine test code — Net power
The Mitsubishi 3A91 was used across Mitsubishi's Global Small Car platform with transverse mounting and licensed to Renault for select European models. This engine received platform-specific adaptations-shortened exhaust manifolds in the Mirage and revised engine mounts in the ASX-and from 2012 the facelifted Colt adopted updated piston rings, creating minor service part distinctions. Partnerships allowed Renault's Twingo and Clio to use a detuned variant. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the crankshaft pulley (Mitsubishi TIS MIVEC‑3A91). The 4th and 5th VIN digits indicate engine displacement ('3A' for 1.2L 3A91 series). Early engines (2008–2011) have silver valve covers with black timing covers; post-2012 units use all-black covers. Critical differentiation from 3A92: 3A91 has 1,193 cc displacement vs. 1,499 cc for 3A92. Service parts require production date verification—piston kits for engines before 06/2012 are incompatible with later units due to ring land redesign (Mitsubishi SB‑09‑12‑003).
The 3A91's primary reliability risk is excessive oil consumption in early builds (2008–2011), with elevated incidence in high-mileage or short-trip urban use. Mitsubishi internal quality data from 2013 indicated up to 12% of pre-2012 engines exceeded 0.5 L/1,000 km consumption, while EU type-approval testing confirmed revised pistons reduced this to <2% in post-2012 units. Extended oil change intervals and low-quality oil accelerate ring coking, making oil specification and interval adherence critical.
Analysis derived from Mitsubishi technical bulletins (2009–2015) and EU type-approval failure statistics (2010–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI 3A91.
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