The scope of this work is to reduce the dynamic friction between the moving parts of the ALH6DTI engine by adding additive in the engine oil. The lubricant additive has the inherent of boric acid used as oil additive in the proportion of 10:1 ratio. SAE 15W40 oil is used as standard engine oil. Interaction of boric acid with the metal surface and water produces a very thin film of boric oxide. Boric oxide film forms corrosive resistant barrier between metal surfaces. Interaction of boric acid with air produces self replenishing of boric acid molecules in the form of acid platelets slide over each other and minimise the dynamic friction. The friction consumption to overcome the friction is considerably reduced. Increase in positive power for the same quantity of fuel injection reflects on the considerable reduction in specific fuel consumption.