MAIN ENGINE IMPROPER FITTING OF THE ‘O’ RINGS ON THE COOLING WATER LINE TO EXHAUST VALVE


This incident happened on a LPG carrier. It was around 1930 hrs, alarm sounded and found the ME jacket cooling water pressure suddenly fluctuating and low pressure alarm being activated. As per the company norms independent watch were kept and I informed chief engineer who rushed down to assess the situation. Checked the expansion tank for any loss of water, but found it was okay, then cooling system was vented at various paints and found the situation improving, and venting continued till the pressures became constant, but at higher speeds pressure started fluctuating. Suspected it may due to crack in one the cylinders heads.

Stopped engines after informing the bridge, and after15 minutes opened up the scavenge spaces and inspected, could not find and trace of water back in any unit, hence boxed back the scavenge spaces, and started engine. Next investigation shifted to locate the unit which was giving this problem. After thorough checking, it was suspected to be unit 4, hence decided to out off #4 unit. After cutting off of the unit, it was found pressure fluctuation had stopped.

Decided to open the unit, and first lifted up the exhaust valve, on removal inspected and found the, ‘O’ ring slightly damaged and traces of exhaust leak. Boxed back the exhaust valve with new ‘o’ ring and made all the connections. Engine started and found no more fluctuation of cooling water pressure. Slowly increased speed and changed over to heavy fuel oil and continued the voyage.
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