Completed furnace, maintenance and inspection. I cleaned flame sensor and wiped down furnace. I checked air pressure and temp splits. I tested components and amp draws. I performed three safety checks on the furnace. While checking out the inducer motor, I noticed that the inducer motor is over amping. The numbers I received while performing the safety checks were on the fringe of being outside of manufacture specs. I performed a visual safety check and found that the AC coil had been dripping onto the heat exchanger for the past six years. This has caused more damage to the heat exchanger than what is normal. There are a couple spots that look like holes in the heat exchanger. I brought out my supervisor to provide a second set of eyes. Supervisor is handling repair options for this visit. Furnace is running at departure.