Mercedes-Benz M104 Engine Specs

The Mercedes-Benz M104 is a naturally aspirated inline-six petrol engine produced from 1985 to 1998, one of Mercedes-Benz's most respected engines of the late 20th century and a defining powerplant of the brand's "over-engineered" reputation from that era. It powered a remarkably wide range of Mercedes models across nearly every body style the company offered at the time, including the W124 E-Class, W140 S-Class, R129 SL, W202 C-Class, and even the W463 G-Class.

Producing 220hp and 280Nm of torque from 2,962cc, the M104 uses a SOHC 24-valve head (four valves per cylinder) and a compression ratio of 10.0:1, resulting in the smooth, refined, and famously robust character that Mercedes inline-sixes of this era are still celebrated for today. Mercedes rated the M104 for an exceptional 400,000km-plus service life, and countless examples in taxi and long-distance fleet service have proven this rating conservative rather than optimistic - it's genuinely common to find M104-powered Mercedes with 500,000km or more on the original engine internals.

Given the M104's now-considerable age, most surviving examples fall into either dedicated enthusiast ownership or continued high-mileage daily use, and maintenance considerations reflect that split. The timing chain, while durable by design, should be inspected for stretch and tensioner wear on any high-mileage example, since a chain issue on this interference engine can eventually cause valve damage if left unaddressed. Cooling system components - radiator, hoses, and water pump - are wear items that should be assessed given the age of any surviving example, particularly if service history is uncertain. Vacuum-operated components, common throughout Mercedes vehicles of this era, can develop leaks with age, sometimes causing minor drivability quirks that are more of an annoyance than a serious concern. Overall, the M104 remains one of the most trusted classic Mercedes engines available, and a well-maintained example represents a genuinely low-risk purchase by classic-car standards.