Mercedes-Benz OM601 / OM602 / OM662

Mercedes' indirect-injection diesels of the 1980s — the four-cylinder OM601, five-cylinder OM602 and six-cylinder OM603 — in the W124 and W201, and licence-built into the SsangYong Musso, Korando and Rexton as the OM661 and OM662.

⚑ That Korean afterlife is why this page exists. SsangYong went on building these long after Mercedes stopped, so a 2000s Korean SUV can carry a 1980s German diesel — and Mercedes parts and Mercedes diagnostic material apply directly, which almost nothing else about those vehicles does. It is the same story as mercedes-m104, which is the petrol six in the same cars.

They are mechanically injected and famously durable. No rail, no filter, nothing to regenerate, and a reputation for very high mileage that is genuinely earned rather than nostalgic.

Their recurring items are old-diesel wear: glow plugs and their relay, an injection pump whose timing drifts with the chain, and injector nozzles that carbon up and knock at idle. The OM60x family is chain-driven, which removes the belt anxiety that defines most diesels of the era.

The wiring harness caution on mercedes-m104 applies here too on the Mercedes-built cars of the early 1990s: biodegradable insulation that crumbles off the loom.