Mercedes Benz Truck R 320 BLUETEC Technical LI03-20_P-0482783 Date: 130326 Diesel Engine - Crackling/Ticking Noise At Idle Engine makes intermittent knocking noise, ticking/crackling Topic number LI03.20-P-048278 Version 3 Design group 03.20 Crankshaft Date 03-26-2013 Validity Model series 211, 219 with OM 642 Model series 164, 251 with OM 642 Model series 203, 204, 209, 221 461 463 with OM 642 Reason for change New part number for upper main bearing shell, bearing point 1 Complaint: The engine makes ticking/crackling noises at idle speed and at speeds up to approx. 1500 rpm. Notes: ^ The noise occurs after a mileage of approx. 20,000 km or after an oil change. ^ Noise can be clearly heard in area of 1st crankshaft main bearing. ^ Noise can no longer be heard when the poly-V belt is removed. ^ It is essential to compare the noise of the complaint vehicle! ^ Noise is irregular. Pulse-like crackling noise occurs at irregular intervals. ^ 20 pulses (ticking) which rep...