Engine performance before and after blower cleaning of turbocharger in main engine was measured in order to evaluate the fuel-saving effect of the detergent cleaning of the blower of the turbocharger. The results showed that there was almost no recognizable difference in the fuel consumption, the rotational frequency of turbocharger, and the maximum pressure of the cylinder for the engine power, however, the intake manifold pressure for the engine power increased and exhaust gas temperature for the engine power decreased. From these results, there was no fuel-saving effect on the blower cleaning of the turbocharger. However, the execution of that cleaning will contribute to the prevention of the accidents of cylinder-head, cylinder-liner, and exhaust valve.