The Mitsubishi 4G52 is a 1,995 cc, inline‑four naturally aspirated petrol engine produced between 1972 and 1989. It features a single overhead camshaft (SOHC), 8 valves, and a cast‑iron block with an aluminum cylinder head. In standard form it delivered 74–81 kW (100–110 PS) and torque figures between 152–162 Nm, offering robust performance for its era.
Fitted to models such as the Mitsubishi Galant, Lancer, and early Pajero (Shogun), the 4G52 was engineered for durabil…
Production years 1972–1982 meet JIS D 1001 standards; 1983–1989 models meet pre‑Euro national standards depending on market (JAMA Type Approval #JAMA/EMS/4G52).
The Mitsubishi 4G52 is a 1,995 cc inline‑four naturally aspirated petrol engine engineered for compact sedans and early SUVs (1972–1989). It combines SOHC valvetrain with a durable cast‑iron block to deliver reliable everyday performance. Designed to meet Japanese JIS and pre‑Euro emissions standards, it prioritizes mechanical simplicity and serviceability over refinement.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,995 cc | |
Fuel type | Petrol (Unleaded or leaded, depending on year) | |
Configuration | Inline‑4, SOHC, 8‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 84.0 mm × 90.0 mm | |
Power output | 74–81 kW (100–110 PS) @ 5,500–6,000 rpm | |
Torque | 152–162 Nm @ 3,500–4,000 rpm | |
Fuel system | Carburettor (early) or throttle-body injection (late) | |
Emissions standard | JIS D 1001 (1972–1982); pre‑Euro national standards (1983–1989) | |
Compression ratio | 8.8:1 (carb), 9.2:1 (EFI) | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain‑driven SOHC | |
Oil type | API SF/SG, SAE 10W‑40 | |
Dry weight | 138 kg |
The Mitsubishi 4G52 was used across Mitsubishi's compact and mid‑size platforms with longitudinal or transverse mounting depending on application. This engine received platform-specific adaptations—reinforced mounts in the Pajero and revised oil pan baffling in the Galant—and from 1983 the facelifted Lancer EX adopted updated cylinder heads, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
The 4G52's primary reliability risk is cylinder head cracking around exhaust valve seats in early builds (1972–1982), with elevated incidence in high-load or overheated use. Mitsubishi internal quality data from 1984 indicated up to 11% of pre-1983 engines exhibited head cracks before 180,000 km, while JAMA durability testing confirmed revised heads reduced this to <2% in post-1983 units. Extended oil change intervals and cooling system neglect accelerate thermal stress, making maintenance adherence critical.
Analysis derived from Mitsubishi technical bulletins (1978–1988) and JAMA durability failure statistics (1980–1995). 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 4G52 is mechanically simple and durable if maintained properly, but early models (1972–1982) had cylinder head cracking issues under thermal stress. Post-1983 revisions resolved this with improved castings. Regular oil and cooling system maintenance greatly improve longevity and prevent common failures.
Key issues include cylinder head cracking (early builds), carburettor malfunctions, timing chain stretch, and distributor advance mechanism seizure. These are documented in Mitsubishi technical bulletins TB‑78‑03‑045 and related TIS entries.
The 4G52 powered the Mitsubishi Galant (1973–1983), Lancer (1973–1983), and early Pajero/Shogun (1983–1989). It was also used in Dodge Colt models (1978–1983) under Chrysler-Mitsubishi partnership agreements.
Yes. The 4G52 responds well to carburettor upgrades, mild camshafts, and exhaust improvements. Stage 1 tuning yields +10–15 kW. Forced induction is possible but requires head reinforcement and fuel system upgrades. Most owners prioritize reliability over significant power gains.
Moderate for its era. In a Galant 2.0 (1980), typical consumption is ~10.2 L/100km (city) and ~7.1 L/100km (highway), or about 28 mpg UK combined. Real-world mixed driving typically returns 25–30 mpg (UK) when maintained properly.
No. The 4G52 is a non-interference engine. If the timing chain fails or jumps, piston-to-valve contact will not occur, reducing catastrophic failure risk. However, valvetrain timing will be lost, requiring re-synchronization.
Mitsubishi specifies SAE 10W-40 oil meeting API SF/SG (or ACEA A2/B2 for EFI variants). Always use a quality mineral oil with good detergent content and change every 7,500 km to minimize sludge and protect the timing chain.
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