Trim / Codes
The Mercedes-Benz 300D (W123) was sold from 1977 to 1985, initially with a naturally aspirated 3.0-liter five-cylinder diesel and, from 1981, a turbocharged variant producing roughly 120 horsepower. Common service items include glow plug and fuel filter replacement, injection pump and injector maintenance, and timing chain inspection on high-mileage engines. These cars are also prone to rust in the floor pans, fenders, and trunk, and aging vacuum and rubber components can affect turbocharged models.
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W123The W123 300D uses a rear-wheel-drive layout with the OM617 five-cylinder diesel engine, paired with either a four-speed manual or four-speed automatic transmission. From 1982, the 300D Turbodiesel added a turbocharger to the same engine family. Typical maintenance focuses on the mechanical fuel injection pump, timing chain tensioner, valve adjustments, and glow plugs, while body rust and vacuum-system leaks on automatic cars are also common concerns.