Subaru Impreza 2004 - Manual (Page 98)

PM-22
PERIODIC MAINTENANCE SERVICES
Coolant
2. RELATIONSHIP OF SUBARU COOLANT
CONCENTRATION AND FREEZING TEM-
PERATURE
The concentration and safe operating temperature
of the SUBARU coolant is shown in the diagram.
Measuring the temperature and specific gravity of
the coolant will provide this information.
[Example]
If the coolant temperature is 25
°C (77°F) and its
specific gravity is 1.054, the concentration is 35%
(point A), the safe operating temperature is
−14°C
(7
°F) (point B), and the freezing temperature is
−20°C (−4°F) (point C).
3. PROCEDURE TO ADJUST THE CON-
CENTRATION OF THE COOLANT
To adjust the concentration of the coolant accord-
ing to temperature, find the proper fluid concentra-
tion in the above diagram and replace the
necessary amount of coolant with an undiluted so-
lution 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 cooling
system and add 2.1
2 (2.2 US qt, 1.8 Imp qt) of the
undiluted solution of SUBARU coolant.
If a coolant concentration of 50% is needed, drain
all the coolant and refill with the undiluted solution
only.
(1) Coolant gravity
(2) Safe operating temperature
(3) Concentration of coolant
(4) Freezing temperature
(5) Coolant temperature
PM-00025
60%
(1.054)
1.000
1.010
1.020
1.030
1.040
1.050
1.060
1.070
1.080
1.090
1.100
(5)
(4)
(3)
(2)
(1)
B
A
C
-40
(-40) (-22) (-4) (14) (32) (50) (68) (86)
( F)
(104) (122)
-30 -20 -10 0 10 20 30 40 50
(77 F)
50%
40%
30%
20%
25 C 10%
C
(1) Quantity of coolant to be drained
(2) Necessary concentration of coolant
(3) Concentration of coolant in vehicle cooling sys-
tem
PM-00026
10
0
1
2
3
(1.1,0.9)
(2.1,1.8)
(3.2,2.6)
10%
15%
25%
20%
30%
35%
40%
45%
A
20 30 40 50
%
(3)
(2)
(1)
(US qt, Imp qt)