Abstract: The smart cap includes at least one replaceable rubber band that is used to plug the smart cap into the oil inlet of the automobile. Because the rubber band can compress and expand inside the oil inlet, the band provides a snug fix to various number oil cap sizes, i.e., the diameter of the oil inlet. Furthermore, the band can be used to grip the inner threads of the oil inlet and plugged in the ear, slot type oil inlets. Once the smart cap is inserted, a funnel can be inserted into the opposite end of the rubber band for pouring the motor oil. The smart cap can also be implemented with slots. These slots are used to insert an adaptor. This adaptor can be made with a wing, ear, and slot type oil cap. Hence, when a car is a wing type oil cap, the smart cap can be inserted with a wing type oil cap to be screwed into the oil valve, and a funnel can be inserted in the opposite end for pouring of the engine oil. The inventive smart cap is particularly useful on engines with baffle plates under the oil valve.