Mitsubishi 4M40 / 4M41

Mitsubishi's 2.8 diesel for the Pajero and L200 — the larger engine that sat alongside the 4D56, and the one difference between them that governs everything else.

The 4M40 is chain-driven; the 4D56 is belt-driven. So the belt discipline that dominates a 4D56's life — and the balance-shaft belt that destroys them — simply does not apply here. A workshop that services a 4M40 to a 4D56 schedule is doing work the engine does not need and missing what it does.

What it does have is a reputation for cracking cylinder heads, and overheating is the trigger. On a vehicle of this age and use — heavily loaded, often towing, often in hot climates — the cooling system's history matters more than the mileage. Coolant loss with no external leak on a 4M40 points at the head, and a pressure test is worth doing before anything is dismantled.

Beyond that it is an unstressed, long-lived indirect and later direct-injection diesel. The injection pump and the glow plug system account for most starting complaints, and neither is dramatic.

The 4M41 is the 3.2-litre member of the same family, in the later Pajero and Pajero Sport — chain-driven like the 4M40 and carrying the same head-cracking risk on an overheated engine. The number says the displacement, not a different design.

⚑ This page holds two engines that stopped twenty years apart. The 4M40 ended in 2006 with the Pajero V60; the 4M41 carried on to 2021 in the V80 and through both the L200 and the Pajero Sport. The window above is the union of the two, so a date inside it does not on its own tell you which engine a car has — the displacement does: 2.8 is the 4M40, 3.2 the 4M41.