Adjusting Coolant Concentration
To adjust the concentration of coolant according to temperature, find the proper fluid concentration in the above diagram and replace the necessary amount of coolant with an undiluted solution of SUBARU genuine coolant (concentration 50). The amount of coolant that should be replaced can be determined by using Fig 1 .
Assume the coolant's concentration levels must be increased from 25% to 40%. Find point A in Fig 1 . Notice the X-axis (25% coolant concentration) intersects with the Y-axis (40% of necessary coolant concentration). Now read the vertical axis scale (Y-axis) as it aligns with point A. It shows that 2.2 qts. (2.1 liters) of coolant must be drained from the system. After draining this amount, add 2.2 qts. (2.1 liters) of undiluted SUBARU coolant, or its equivalent.
If a coolant concentration of 50% is needed, drain all the coolant and refill with the undiluted solution only.