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Mitsubishi 6G74 engine: known problems

Used in 2 guides · 3497cc petrol · 6 known problems

Displacement

3497cc

Layout

V6 NA

Fuel

petrol

Known problems6

Everything our guides list for the variants with this engine: the engine itself plus the gearbox and ancillaries it's paired with. Each shows which cars it's listed for.

High

Timing belt failure (interference engine)

Belt-driven and interference - an overdue belt that lets go bends valves and damages heads. Tensioner failure is a common trigger.

Fix: Replace belt, tensioner and water pump on interval (~90,000km or by age); confirm history before purchase.

Any overdue belt · ~$500-1000 service / $3500+ if it snaps

Listed for: Mitsubishi Pajero NA-NG / NH-NL

High

Timing belt neglect (interference engine)

The 6G74 is belt-driven and an interference design - a snapped or skipped belt bends valves and can wreck the engine. Many high-km examples have uncertain belt history.

Fix: Replace the timing belt, tensioner and water pump on schedule (~90k km); confirm belt history before buying.

From 90k km / overdue belts · ~$600-1200 (service) / engine damage if it snaps

Listed for: Mitsubishi Pajero NM-NP

Medium

GDI carbon build-up and rough running

The direct-injection GDI 6G74 accumulates carbon on intake ports, EGR and injectors, causing rough idle, hesitation, poor economy and fault codes.

Fix: Intake/EGR decarbon, injector service and quality fuel; some owners revert tuning or service the GDI system periodically.

From 100k+ km (GDI) · ~$400-1500

Listed for: Mitsubishi Pajero NA-NG / NH-NL

Medium

GDI carbon build-up / fussy running

GDI (direct-injection) versions can suffer intake/valve carbon and become fussy on lower-quality fuel, causing rough running and hesitation.

Fix: Use quality fuel, decarbonise as needed; some owners prefer the non-GDI builds.

From 120k+ km · ~$300-1000

Listed for: Mitsubishi Pajero NM-NP

Low

Intake swirl/idle components and sensors

Intake-manifold flaps, idle control and various sensors age and cause idle and driveability faults on these older V6s.

Fix: Diagnose and replace failing intake/idle components and sensors.

From 120k+ km · ~$300-1000

Listed for: Mitsubishi Pajero NA-NG / NH-NL

Low

Fuel thirst

Real-world 14-17 L/100km, worse when towing - not a fault but a real cost.

Fix: Fit LPG or accept the fuel bill.

Any · Running cost

Listed for: Mitsubishi Pajero NM-NP

Cars with the 6G742

Mitsubishi Pajero NA-NG / NH-NL (1st-2nd gen)

1983-2000 · 3.5L 6G74 V6 petrol (2nd gen)

Value

Mitsubishi Pajero NM-NP (3rd gen)

2000-2006 · 3.5L 6G74 V6 petrol

Value

From the FlamingCars guides for these cars. Specs are shown only where the guides agree and the value is verified.