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Mitsubishi 4M41 engine: known problems

Used in 3 guides · 3200cc diesel · 8 known problems

Displacement
3200cc
Layout
I4 turbo
Fuel
diesel

Known problems8

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 chain guide wear / chain jump
The 4M41 uses a hard-plastic upper timing-chain guide in the head to damp noise. Over time the plastic wears thin and breaks away; the debris can jam the chain set, causing the chain to jump timing and the valves to hit the pistons - a catastrophic engine failure. A worn tensioner gives a tell-tale rattle on start-up/idle.
Fix: Inspect the chain/guide and tensioner; measure chain slack (replace when clearance drops toward ~9mm). Replace guides, tensioner and chain preventively as a set. Treat any timing rattle as urgent.
From 150k-250k km · ~$2000-4000 (preventive) / $10000+ (after failure)
Listed for: Mitsubishi Pajero NM-NP · Mitsubishi Pajero NS / NT / NW / NX
High
Injector failure / melted pistons
Worn or failing injectors cause rough idle, smoke, hard starting and power loss; symptoms can come on quickly. A leaking/over-fuelling injector can melt a piston and blow the engine. Many specialists recommend replacing injectors at 'half life'.
Fix: Replace injectors (set) at the first sign of trouble or preventively around 200k km; use quality fuel and good filtration.
From 200k-250k km (can be earlier) · ~$2000-4000 (injectors) / much more if a piston is melted
Listed for: Mitsubishi Pajero NM-NP
Medium
Injection pump wear
The mechanical/rotary injection pump is regarded as the engine's weakest high-km link, causing hard starting, rough running and lost power as it wears.
Fix: Diesel-specialist pump overhaul or replacement; a pre-emptive rebuild is cheaper than a new pump.
From 250k+ km · ~$1500-3000
Listed for: Mitsubishi Pajero NM-NP
Medium
EGR / intake carbon build-up
Soot from the EGR accumulates in the intake manifold over time, restricting airflow and dulling response.
Fix: Intake/EGR clean; catch-can and (where legal) EGR management help.
From 120k+ km · ~$300-800
Listed for: Mitsubishi Pajero NM-NP
Medium
DPF clogging on short trips (NS/NT)
The DPF won't regenerate properly on repeated short runs; it soot-loads and triggers forced regens. The NT improved the design before the DPF was later dropped.
Fix: Do regular 20km+ runs to allow regen; address soot loading early. Some later cars don't have a DPF.
Any (DPF cars) · ~$500-2000
Listed for: Mitsubishi Pajero NS / NT / NW / NX
Medium
Engine oil dilution from regen
Interrupted/short-trip regens dump fuel into the sump, raising and thinning the oil level over time.
Fix: Check oil level/condition regularly; shorten oil-change interval if used mostly for short trips.
Any (DPF cars on short trips) · Maintenance
Listed for: Mitsubishi Pajero NS / NT / NW / NX
Medium
Injector and pump wear (high km)
Injectors and the high-pressure pump wear at high km, causing rough running and smoke.
Fix: Rebuild pump/injectors preventively before failure - the engine then easily runs well past 300k.
From 200k+ km · ~$1500-3500
Listed for: Mitsubishi Pajero NS / NT / NW / NX
Medium
4M41 EGR/PCV carbon buildup
EGR gas mixes with PCV oil mist causing heavy carbon buildup in intake.
Fix: Walnut blast clean. Catch can fitment helps.
From 100k+ km · ~$600-1200
Listed for: Mitsubishi Triton ML / MN

Cars with the 4M413

Mitsubishi Pajero NM-NP (3rd gen)
2000-2006 · 3.2L DiD 4M41 turbo diesel (NP)
Value
Mitsubishi Pajero NS / NT / NW / NX (4th gen)
2006-2021 · 3.2L 4M41 DI-D turbo diesel
Value
Mitsubishi Triton ML / MN
2006-2015 · 3.2L 4M41 (common-rail turbo diesel)

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