This disclosure provides methods and systems for using coatings to control component dimensions during operations of a mechanical system, such as gas turbine combustion air cooling system. The mechanical system may have a component with a critical dimension defined by at least one surface. Upon detecting a change in the critical dimension, such as from surface erosion, a coating additive is deployed into the mechanical system. The surface is coated with the coating additive to offset at least a portion of the change in the critical dimension.