3. Mercedes OM617 Diesel – The Million-Kilometer Legend
The Mercedes-Benz OM617 engine, produced from 1974 to 1991, is renowned for its exceptional durability and longevity. (en.wikipedia.org) This 3.0-liter inline-five diesel engine powered various models, including the W123 300D and W126 300SD, and is often celebrated for its mechanical simplicity and overbuilt construction. (slashgear.com)
Despite its robust design, the OM617 does have some known issues. Early versions (pre-1979) experienced cracks in the cylinder block near the fifth cylinder and instances of crankshaft breakage. (enginedna.com) Additionally, the engine is prone to oil leaks, particularly from the rear crankshaft oil seal, and may exhibit slow warm-up times. (enginedna.com)
Nevertheless, the OM617’s reputation for reliability remains unmatched. Many owners report their vehicles surpassing 500,000 miles with routine maintenance, and some examples have even exceeded 1 million kilometers. (slashgear.com) This enduring performance has solidified the OM617’s status as a legendary engine in automotive history.
For a visual exploration of the OM617’s enduring legacy, you might find the following video insightful: