The Mitsubishi 4G32 is a 1,597 cc, inline‑four naturally aspirated petrol engine produced between 1971 and 1989. It features a single overhead camshaft (SOHC), 8 valves, and a carbureted fuel system throughout its production run. In standard form it delivered 55–77 kW (75–105 PS) and 118–137 Nm of torque, emphasizing mechanical simplicity and global serviceability.
Fitted to models such as the Galant, Lancer, and Colt, the 4G32 was engineered for cost‑effective ownership in compact sedans and coupes across Asia, Europe, and Oceania. Emissions compliance in later variants was achieved through rudimentary air injection and lean‑burn carburetion, allowing limited compliance with pre‑Euro and early Euro 1 standards in select export markets.
One documented concern is premature wear of the camshaft lobe and tappet surfaces under high‑load or infrequent oil changes, highlighted in Mitsubishi Technical Service Bulletin TSB‑ME‑79‑004. This issue is linked to marginal oil film strength in the flat‑tappet valvetrain design and was partially mitigated from 1983 onward with revised camshaft metallurgy and updated valve spring rates.
Production years 1971–1988 meet pre‑Euro standards; 1989 models may meet Euro 1 depending on market (VCA UK Type Approval #VCA/EMS/1503).
The Mitsubishi 4G32 is a 1,597 cc inline‑four naturally aspirated petrol engine engineered for compact sedans and coupes (1971–1989). It combines a durable cast‑iron block with SOHC valvetrain and carbureted induction to deliver predictable performance and ease of maintenance. Designed to meet pre‑Euro and limited Euro 1 standards, it prioritizes mechanical reliability over emissions sophistication.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,597 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 79.5 mm | |
| Power output | 55–77 kW (75–105 PS) @ 5,500–6,000 rpm | |
| Torque | 118–137 Nm @ 3,500–4,000 rpm | |
| Fuel system | Single or twin-barrel carburetor | |
| Emissions standard | Pre‑Euro (1971–1988); Euro 1 (1989, market-dependent) | |
| Compression ratio | 8.8:1 – 9.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven camshaft (maintenance‑free design) | |
| Oil type | API SF/CC (SAE 10W‑40 mineral) | |
| Dry weight | 118 kg |
The SOHC flat-tappet valvetrain offers mechanical simplicity but requires strict adherence to 10,000 km oil change intervals using API SF/CC 10W-40 mineral oil to prevent cam lobe wear. Carbureted induction demands periodic jet cleaning and float adjustment, especially with modern ethanol-blended fuels. The chain-driven timing system is robust but offers no variable valve timing benefits. Use of leaded fuel substitutes is unnecessary; all variants are designed for unleaded petrol. The cast-iron block ensures longevity but adds weight compared to later aluminum designs.
Oil Specs: Requires API SF/CC mineral oil (10W-40) per Mitsubishi TSB-ME-79-004. Synthetic oils not recommended for flat-tappet camshafts.
Emissions: Euro 1 certification applies only to select 1989 export models (VCA Type Approval #VCA/EMS/1503). Most units are pre-regulation.
Power Ratings: Measured under ISO 1585 standards. Output varies by carburetor configuration and market (Mitsubishi TIS Doc. ME-G32-01).
Mitsubishi Technical Information System (TIS): Docs ME-G32-01, M05-1120, TSB-ME-79-004
VCA Type Approval Database (VCA/EMS/1503)
ISO 1585: Road vehicles — Engine test code
The Mitsubishi 4G32 was used across Mitsubishi's Galant, Lancer, and Colt platforms with transverse or longitudinal mounting depending on model. This engine received platform-specific adaptations—revised engine mounts in the Galant Sigma and modified air cleaner boxes in the Lancer EX—and from 1983 the updated camshaft metallurgy improved valvetrain durability, creating minor interchange limits for cam and lifter components. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the block near the timing cover (Mitsubishi TIS ME-G32-01). The 7th VIN digit is '2' for 4G3x series. Visual cues: black cast-iron block, SOHC valve cover with single breather hose, carburetor with manual choke (early) or automatic choke (late). Critical differentiation from 4G33: 4G32 has 1,597 cc displacement (vs. 1,755 cc) and smaller bore. Pre-1983 camshafts (casting number ending in 'A') are prone to lobe wear; post-1983 units use 'B' suffix per TSB-ME-79-004.
The 4G32's primary reliability risk is camshaft lobe wear on pre‑1983 builds, with elevated incidence in high‑load or poorly maintained vehicles. Mitsubishi internal service data from 1981 indicated a notable share of early Galant and Lancer units required cam replacement before 100,000 km, while UK DVSA records show minimal emissions failures due to mechanical simplicity. Extended oil intervals and use of incorrect oil increase cam wear, making fluid maintenance critical.
Analysis derived from Mitsubishi technical bulletins (1979–1989) and UK DVSA failure statistics (1995–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI 4G32.
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