The Ultimate Guide to the Mercedes Benz OM 352 Engine: Why You Need the Service Repair Shop Manual (ZIP)

Introduction: The Legend of the OM 352

For over five decades, the Mercedes-Benz OM 352 has been hailed as one of the most robust, reliable, and enduring diesel engines ever produced. Known internally as the "Straight-6 Million Kilometer Engine," this 5.7-liter (later 5.8L) indirect injection diesel powerplant served as the backbone for countless vehicles, including the iconic Unimog (U-1100, U-1300), the L-Series trucks (LK, LP, LA), the MB-Trac agricultural tractor, and numerous industrial applications like compressors, pumps, and generators.

A comprehensive workshop manual for the OM 352, OM 353, and OM 362 engines typically spans over 200 pages and includes technical diagrams and torque sequences. Key chapters usually include: OM352 and OM366 Engine Specifications | PDF - Scribd

Understanding the baseline specs is the first step in any repair project. The OM 352 family includes various trim levels, such as the naturally aspirated OM 352, the turbocharged OM 352 A, and the intercooled OM 352 LA. Specification Type 6-cylinder, 4-stroke direct injection diesel Displacement 5,672 cc (approx. 5.7 Liters) Bore x Stroke 128.0128.0 Compression Ratio 17:1 (Naturally Aspirated); 16:1 (Turbocharged) Firing Order 1-5-3-6-2-4 Valve Clearance (Cold) mm / Exhaust: What to Expect in a Professional Shop Manual

  1. Injection Pump Timing: The Bosch inline pump requires specific dial-gauge timing. Off by 1 degree results in knocking, smoke, or loss of power.
  2. Valve Clearance: The OM 352 requires cold valve adjustments with a specific sequence due to the firing order (1-5-3-6-2-4).
  3. Cylinder Liner Protrusion: This engine uses shims under the cylinder liners. Without the factory spec for liner protrusion (above the block deck), you will blow head gaskets repeatedly.
  4. Torque-to-Yield Head Bolts: The OM 352 uses specific torque angles (e.g., 120 Nm + 90° + 90°). Generic manuals often skip the angle torquing, leading to warped heads.