Mercedes OM642 Oil Cooler Leak – Full Repair Guide (ML350 W166 BlueTec)

Complete DIY repair guide covering my efforts to diagnose and repair the common OM642 oil cooler leak on my 2014 W166 ML350 BlueTEC. At the time of repair the car had: 100,000 km / 60,000 miles Original oil cooler seals Significant oil leaking into the engine valley This was my first time doing the job and it took around 30–40 hours from start to finish. The full video combines all 7 parts of the repair series: Part 1 – Preparation, coolant & oil drain, battery & bulkhead removal Part 2 – Removing PCV, EGR, mixer pipe, turbo & fuel system Part 3 – Inlet manifold & oil cooler removal Part 4 – Reassembly of cooler, manifold, fuel system, EGR & turbo Part 5 – Reassembly of EGR, PCV, mixer & wiring Part 6 – First startup, wrap-up & spare parts discussion Part 7 – Follow-up and final results A huge job, but very achievable for a careful DIY mechanic with patience and plenty of labeling/photos during teardown. Torque Settings I Used: Oil Cooler to Engine Block (E10) – 12 Nm Inlet Manifolds to Cylinder Head (E10) – 16 Nm Turbo Pedestal to Engine Block (T45) – 12 Nm Turbo to Pedestal (E10) – Stage 1: 30 Nm / Stage 2: 50 Nm (Some sources specify +120° instead of final torque) Turbo Bracket to Engine Block – 16 Nm Turbo to Exhaust Manifolds – 20 Nm + 90° Turbo Elbow to Downpipe – 20 Nm EGR Flexi Elbow to Intake Side (E10) – 10 Nm + 1/4 turn EGR Flexi Elbow to Exhaust Side (E10) – 20 Nm Fuel Rails to Valve Covers – 9 Nm Fuel Rail Nuts – 20 Nm (Some sources specify +60° additional turn) Oil Cooler Complete Gasket Sets: #(ad) https://amzn.to/3ZIJJEs https://amzn.to/4rOhNux https://amzn.to/4r9DGUZ Common symptoms of OM642 oil cooler seal failure: Oil smell through vents Oil pooling in engine valley Oil leaks down rear of engine Burning oil smell after driving Gradual oil loss Applicable to many Mercedes OM642 diesel vehicles including: ML350 Diesel GLE350d GL350 Sprinter V6 Diesel #ml350 #w166 #om642 #oilcooler #oilleak #mercedesbenz #bluetec #diesel #diymechanic