Flushing your vehicle’s cooling system is something you should do on a regular basis. If you have a separate coolant tank, you should flush it as well. The reservoir tank on a Subaru Outback doesn’t have a drain plug, but you can remove the tank and drain it.
Tools Used: Tools, 3/8-inch ratchet and sockets, Bucket, Hose and water source, Coolant, Distilled water
Drain a Reservoir Tank
Pop the hood, and remove the reservoir tank cap from the reservoir tank. A long rubber hose connects the tank to the radiator; when you pull off the cap, this hose will come out with it. Place the hose to the side.