an automated system for rapidly and safely evacuating used fluid from the drain plug opening of a fluid receptacle and replenishing the fluid receptacle with fresh fluid through the same drain plug opening . the automated fluid changing system includes an evacuation means for withdrawing the used fluid from the drain plug opening , a dispensing means for dispensing fresh fluid into the fluid receptacle through the drain plug opening , valve means for controlling the flow of fluids into and out of the fluid receptacle , and electronic control means which is in communication with the valve means , the evacuation means , and the dispensing means for automatically directing each phase of the fluid changing procedure . the evacuation means includes a suction pump for applying a suction force to withdraw the used fluid . the dispenser means includes a pump for dispensing the fluid into the fluid receptacle under pressure . the fluid changing system may be configured to dispense several different types of fluid , and is particularly suitable for dispensing automotive fluids , such as different grades of oil . air pressure from an external source is used to force all of the fresh fluid out of the dispenser means and into the fluid receptacle to prevent any substantial amount of the fresh fluid from mixing with a different type of fluid which may subsequently be dispensed through the fluid changing system . a computer controller automatically initiates the evacuation of the used fluid and the dispensing of fresh fluid upon receipt of appropriate instructions by an operator via a user interface panel .