Evaluation of Cooling Water System Maintenance on Marine Diesel Engines in Plateau State Boat Services

The cooling water system is vital to the thermal management and reliable operation of marine diesel engines, and its neglect is a principal cause of engine overheating and failure. This study evaluates cooling water system maintenance practices on marine diesel engines aboard passenger and fishing boats operating on the lakes and dams of Plateau State, North Central Nigeria, including Shere Hills Dam and Naraguta Reservoir. A descriptive survey design was adopted, using structured interviews with fifty boat operators and mechanics, physical inspection of cooling systems on twenty boats, and collection of coolant samples for chemical analysis. Assessments covered raw water strainer maintenance, heat exchanger condition, thermostat functionality, raw water pump impeller condition, and coolant inhibitor levels. Findings reveal that the majority of operators have no formalised cooling system maintenance schedule, relying on visual observation of engine temperature gauges as the sole monitoring tool. Coolant samples from all tested boats showed depleted corrosion inhibitor levels, and scaling was evident in heat exchanger cores of twelve of the twenty inspected engines. Raw water pump impellers had not been replaced within the manufacturer-recommended seasonal interval on any of the inspected boats. Engine overheating was identified as the most common mechanical complaint by operators. Recommendations include development and distribution of a simplified maintenance checklist for cooling systems in local languages, provision of cooling system maintenance training through the Plateau State Agricultural Development Programme, and encouragement of cooperative spare parts purchasing. Keywords: cooling water system, marine diesel engines, Plateau State, engine maintenance, overheating