The Mitsubishi 4G12 T is a 1,597 cc, inline‑four turbo‑petrol engine produced between 1983 and 1991. It features a cast‑iron block, SOHC 8‑valve architecture, and a mechanically controlled TD04 turbocharger. In standard form it delivered 88–92 kW (120–125 PS) and 186–196 Nm of torque, with strong mid‑range pull suited for sporty compact applications.
Fitted to models such as the Lancer EX (A17#), Galant Σ/Eterna (A18#), and Cordia (A16#), the 4G12 T was engineered for s…
Production years 1983–1991 predate formal Euro emissions standards; engines comply with Japanese ECV regulations and UK pre‑Euro type approvals (VCA UK Type Approval #VCA/EMS/1872).
The Mitsubishi 4G12 T is a 1,597 cc inline‑four turbo‑petrol engine engineered for sporty compact sedans and coupes (1983–1991). It combines SOHC architecture with a TD04 mechanical turbocharger to deliver responsive mid‑range torque and period‑appropriate performance. Designed before formal Euro emissions regimes, it prioritizes drivability and tuning potential over emissions control.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,597 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | Inline‑4, SOHC, 8‑valve | |
Aspiration | Turbocharged (mechanical wastegate) | |
Bore × stroke | 78.4 mm × 83.0 mm | |
Power output | 88–92 kW (120–125 PS) @ 5,500 rpm | |
Torque | 186–196 Nm @ 3,000 rpm | |
Fuel system | Carburetor or ECI-Multi electronic injection | |
Emissions standard | Pre‑Euro (Japanese ECV compliant) | |
Compression ratio | 8.0:1 | |
Cooling system | Water‑cooled | |
Turbocharger | Mitsubishi TD04-09B (mechanical actuator) | |
Timing system | Belt‑driven camshaft | |
Oil type | API SF/SG, SAE 10W‑40 | |
Dry weight | 142 kg |
The Mitsubishi 4G12 T was used across Mitsubishi's A-series performance platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—reinforced sump baffling in the Lancer EX and upgraded intercooling in the Cordia—and from 1987 the Galant Σ received the MLS head gasket upgrade, creating minor service part interchange limits. All adaptations are documented in OEM technical bulletins.
The 4G12 T's primary reliability risk is head gasket failure due to thermal stress under boost, with elevated incidence in sustained high-load or tropical climates. Mitsubishi internal field data from 1986 indicated up to 15% of early units required gasket replacement before 80,000 km, while UK DVLA records show frequent cooling system repairs in imported examples. Extended boost use and marginal coolant flow accelerate gasket degradation, making gasket type and coolant maintenance critical.
Analysis derived from Mitsubishi technical bulletins (1984–1989) and UK DVLA/DVSA failure statistics (1990–2000). 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 4G12 T offers spirited performance but requires diligent maintenance. Early units (1983–1986) are prone to head gasket failure, while post-1987 MLS gasket versions are significantly more robust. With regular timing belt changes (every 60,000 km), quality oil, and proper cooling system care, many examples exceed 200,000 km.
Top issues include head gasket blowouts (early builds), timing belt failure due to interference design, turbo oil seal leaks, and carburetor tuning problems. All are documented in Mitsubishi TSBs and can be mitigated with OEM-specified parts and proactive service.
The 4G12 T appears in the Lancer EX (1983–1987), Galant Σ/Eterna (1983–1991), Cordia (1983–1989), and Tredia (1983–1987). It was never licensed to other manufacturers and was replaced by the 4G63T in performance applications by 1988.
Yes. The low 8.0:1 compression and robust block allow safe boost increases. Stage 1 tuning (wastegate adjustment, fuel enrichment) typically yields +15–20 kW. Many owners upgrade to 4G63T components (injectors, ECU) for greater reliability and power potential.
Moderate for a turbo petrol of its era. In a Cordia 1600 Turbo, expect ~10.8 L/100km (city) and ~7.5 L/100km (highway), or about 26 mpg UK combined. Real-world mixed driving typically returns 24–28 mpg (UK), depending on boost usage and driving style.
Yes. The 4G12 T is an interference engine. If the timing belt fails, pistons will contact open valves, causing severe internal damage. This makes strict adherence to the 60,000 km belt replacement interval essential.
Mitsubishi specifies API SF/SG petrol-rated oil, typically SAE 10W‑40. Always use a quality mineral or semi-synthetic oil and change every 5,000–7,500 km to protect the turbo bearings and maintain engine cleanliness.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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