3.2 Initial commissioning Operation Trial run Venting of the fuel system by operating for 5 minutes at idle speed or low load is absolutely necessary. After preparations, perform a short trial run up to operating temperature (approx. 90 °C). Do not apply load to the engine if possible. z Work with the engine not running: Check engine for tightness. Check oil level, re-fill oil if necessa- ry ( 29 ) . Check coolant level and refill coolant if necessary ( 34 ) . z Work during the trial run: Check engine for tightness. 3 17