Viscosity plays an important role in filtration because it impacts the speed at which the fluid can be pushed through a filter to remove contaminants. As fluid viscosity increases, the flow rate that is pumped through a filter must be decreased. This is because higher viscosity fluids have a higher resistance to flow resulting in a higher pressure drop and shorter filter life. Selecting a filter with a larger micron size will help decrease the pressure drop since there will be less resistance moving through the filter.