Abstract: For cooling of internal combustion (I.C) engines either air or a liquid is employed to remove the waste heat. Cooling is very much essential because high temperatures damage engine materials and lubricants. Cooling becomes more important when the climate becomes very hot. IC engines burn fuel hotter than the melting temperatures of engine materials and it is hot enough to set fire to lubricants. Engine cooling removes heat energy fast enough to keep temperatures low so that the engine can survive. A cooling curve test was performed in order to find the effect of using different types of coolants in I.C engines. The types of coolants used for this test were: (1).Water (2).Ethylene glycol based coolants. Coolant concentration of 50% in ethylene glycol was examined. The experiment was conducted on kirloskar made 4 stroke single cylinder vertical hand cranking type diesel engine. The main focus of this experiment was to determine the rate of heat carried away by coolant and specific fuel consumption. Temperature of coolant at outside was varied, while the speed of engine was kept constant. To achieve a particular temperature for ethylene glycol based coolant, the flow rate was made to reach a required value and it was compared with the flow rate of water.

Keywords: IC engine, coolant, ethylene glycol based coolants, heat carried, Specific fuel consumption, cooling curve test.