Subaru Legacy 2004 Service Manual page 124

2. RERATIONSHIP OF SUBARU COOLANT
CONCENTRATION AND FREEZING TEM-
PERTAURE
Concentration and safe operating temperature of
SUBARU coolant is shown in the diagram. Measur-
ing the temperature and specific gravity of the cool-
ant will provide this information.
[Example]
If the coolant temperature is 25#C (77#F), its specif-
ic gravity is 1.054 and the concentration is 45%
(point A), the safe operating temperature is $14#C
(7#F) (point B), and the freezing temperature is
$20#C ($4#F) (point C).
Safe operating temperature
1.100
1.090
1.080
1.070
B
C
1.060
(1.054)
1.050
1.040
Freezing
1.030
temperature
1.020
1.010
1.000
-40
-20 -10
-30
(-40) (-22) (-4) (14) (32) (50) (68) (86)
Coolant temperature
3. PROCEDURE TO ADJUST THE CON-
CENTRATION OF THE COOLANT
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 using the diagram.
[Example]
Assume that the coolant concentration must be in-
creased from 25% to 40%. Find point A, where the
25% line of coolant concentration intersects with
the 40% curve of the necessary coolant concentra-
tion, and read the scale on the vertical axis of the
graph at height A. The quantity of coolant to be
drained is 2.1 2 (2.2 US qt, 1.8 Imp qt). Drain 2.1
2 (2.2 US qt, 1.8 Imp qt) of coolant from the cool-
ing system and add 2.1 2 (2.2 US qt, 1.8 Imp qt) of
the undiluted solution of SUBARU coolant.
Engine Coolant
Concentration
of coolant
60%
50%
A
40%
30%
20%
10%
0 10 20 30 40 50
(104) (122)
C ( F)
CO-00237
PERIODIC MAINTENANCE SERVICES
If a coolant concentration of 50% is needed, drain
all the coolant and refill with the undiluted solution
only.
3
(3.2,
2.6)
2
(2.1,
1.8)
1
(1.1,
0.9)
10% 15%
0
Concentration of coolant in
the vehicie cooling system %
Concentration of coolant in vehicie
and quantity to be drained
PM-23
Necessary Concentration
of coolant
45%
A
40%
35%
30%
25%
20%
10 20 30 40 50
CO-00012