The intake noise of engine fixed with different acoustical loads was measured and the intake acoustical source was extracted using the fourload least squares method. The calculated and experimental values of the intake noise when fixed with one load were compared. The comparison results show that at most of the frequency range, the simulation values agree well with the experimental ones, indicating that  the acoustical source extracted is reliable. By taking into consideration the intake acoustical source and by culculating the acoustical characteristics of the original air-cleaner using the FEM approach, the order components of intake noise was computed. The frequencies where the noise needed to be lowered were found. Finally, the noise was reduced by adding or better designing noise eliminating elements.