1999 SUBARU LEGACY engine coolant

4) Drain engine coolant completely.

B2M0015A
5) Disconnect connectors from radiator main fan
(A) and sub fan (B) motors.
B2M2035A
6) Loosen bolts which hold lower side of radiator
main fan and sub fan shrouds.
B2M2041
7) Disconnect radiator outlet hose (A) and heater
by-pass hose (B) from water pump.
H2M2515A
8) Lower the vehicle.
9) Remove radiator main fan [W6A0].> and sub fan assemblies [W7A0].>.
B2M2036
10) Remove V-belts.

B2M2308
11) Remove timing belt.

S2M0017
12) Remove automatic belt tension adjuster.
H2M2403
11
[W2A2]2-5SERVICE PROCEDURE
2. Water Pump

3) Using a dial gauge, measure impeller runout in
thrust direction while rotating the pulley.
ªThrustº runout limit:
0.5 mm (0.020 in)
G2M0211
4) Check clearance between impeller and pump
case.
Clearance between impeller and pump case:
Standard
0.5 Ð 0.7 mm (0.020 Ð 0.028 in)
Limit
1.0 mm (0.039 in)
G2M0212
5) After water pump installation, check pulley shaft
for engine coolant leaks. If leaks are noted, replace
water pump assembly.
3. Thermostat
A: REMOVAL AND INSTALLATION
1) Drain engine coolant.
Set container under the vehicle, and remove drain
cock from radiator.
2) Disconnect radiator outlet hose from thermostat
cover.
3) Remove thermostat cover and gasket, and pull
out the thermostat.
G2M0214
4) Install the thermostat in the intake manifold,
and install the thermostat cover together with a
gasket.
CAUTION:
IWhen reinstalling the thermostat, use a new
gasket.
IThe thermostat must be installed with the
jiggle pin upward.
IIn this time, set the jiggle pin of thermostat
for front side.
G2M0227
13
[W3A0]2-5SERVICE PROCEDURE
3. Thermostat

3) Using a dial gauge, measure impeller runout in
thrust direction while rotating the pulley.
ªThrustº runout limit:
0.5 mm (0.020 in)
G2M0211
4) Check clearance between impeller and pump
case.
Clearance between impeller and pump case:
Standard
0.5 Ð 0.7 mm (0.020 Ð 0.028 in)
Limit
1.0 mm (0.039 in)
G2M0212
5) After water pump installation, check pulley shaft
for engine coolant leaks. If leaks are noted, replace
water pump assembly.
3. Thermostat
A: REMOVAL AND INSTALLATION
1) Drain engine coolant.
Set container under the vehicle, and remove drain
cock from radiator.
2) Disconnect radiator outlet hose from thermostat
cover.
3) Remove thermostat cover and gasket, and pull
out the thermostat.
G2M0214
4) Install the thermostat in the intake manifold,
and install the thermostat cover together with a
gasket.
CAUTION:
IWhen reinstalling the thermostat, use a new
gasket.
IThe thermostat must be installed with the
jiggle pin upward.
IIn this time, set the jiggle pin of thermostat
for front side.
G2M0227
13
[W3A0]2-5SERVICE PROCEDURE
3. Thermostat

B: INSPECTION
Replace the thermostat if the valve does not close
completely at an ambient temperature or if the fol-
lowing test shows unsatisfactory results.
Immerse the thermostat and a thermometer in
water. Raise water temperature gradually, and
measure the temperature and valve lift when the
valve begins to open and when the valve is fully
opened. During the test, agitate the water for even
temperature distribution. The measurement should
be to the specification.
Starts to open:
76.0 Ð 80.0ÉC (169 Ð 176ÉF)
Fully opens:
91ÉC (196ÉF)
H2M2357A
(A) Thermometer
(B) Thermostat
4. Radiator
A: REMOVAL
1) Disconnect battery ground cable.
B2M1723
2) Lift-up the vehicle.
3) Remove under cover.
B2M0014
4) Drain engine coolant completely. [W1A0].>
B2M0015A
14
2-5[W3B0]SERVICE PROCEDURE
4. Radiator

B: INSPECTION
Replace the thermostat if the valve does not close
completely at an ambient temperature or if the fol-
lowing test shows unsatisfactory results.
Immerse the thermostat and a thermometer in
water. Raise water temperature gradually, and
measure the temperature and valve lift when the
valve begins to open and when the valve is fully
opened. During the test, agitate the water for even
temperature distribution. The measurement should
be to the specification.
Starts to open:
76.0 Ð 80.0ÉC (169 Ð 176ÉF)
Fully opens:
91ÉC (196ÉF)
H2M2357A
(A) Thermometer
(B) Thermostat
4. Radiator
A: REMOVAL
1) Disconnect battery ground cable.
B2M1723
2) Lift-up the vehicle.
3) Remove under cover.
B2M0014
4) Drain engine coolant completely. [W1A0].>
B2M0015A
14
2-5[W3B0]SERVICE PROCEDURE
4. Radiator

2) Release motor harness from shroud.
B2M2048
3) Remove bolts which install fan motor onto
shroud.
B2M2055
4) Assembly is in the reverse order of disassem-
bly.
Tightening torque:
4.4
±0.5 N´m (0.45±0.05 kg-m, 3.3±0.4 ft-lb)
B2M2055
8. Water Pipe
A: REMOVAL
1) Release fuel pressure.

2) Disconnect ground cable from the battery.
G6M0095
3) Drain engine coolant completely.

B2M0015A
4) Remove intake manifold.

B2M0160
23
[W8A0]2-5SERVICE PROCEDURE
8. Water Pipe

2) Release motor harness from shroud.
B2M2048
3) Remove bolts which install fan motor onto
shroud.
B2M2055
4) Assembly is in the reverse order of disassem-
bly.
Tightening torque:
4.4
±0.5 N´m (0.45±0.05 kg-m, 3.3±0.4 ft-lb)
B2M2055
8. Water Pipe
A: REMOVAL
1) Release fuel pressure.

2) Disconnect ground cable from the battery.
G6M0095
3) Drain engine coolant completely.

B2M0015A
4) Remove intake manifold.

B2M0160
23
[W8A0]2-5SERVICE PROCEDURE
8. Water Pipe

1. Engine Cooling System Trouble in General
TroubleCorrective action
Over-heatinga. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt Repair or replace timing belt tensioner.
c. Oil on drive belt Replace.
d. Malfunction of thermostat Replace.
e. Malfunction of water pump Replace.
f. Clogged engine coolant passage Clean.
g. Improper ignition timingInspect and repair ignition control system.
On-Board Diagnostics II System
h. Clogged or leaking radiator Clean or repair, or replace.
i. Improper engine oil in engine coolant Replace engine coolant.
j. Air/fuel mixture ratio too leanInspect and repair fuel injection system.
On-Board Diagnostics II System
k. Excessive back pressure in exhaust system Clean or replace.
l. Insufficient clearance between piston and cylinder Adjust or replace.
m. Slipping clutch Repair or replace.
n. Dragging brake Adjust.
o. Improper transmission oil Replace.
p. Defective thermostat Replace.
q. Malfunction of electric fanInspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-coolinga. Atmospheric temperature extremely low Partly cover radiator front area.
b. Defective thermostat Replace.
Engine coolant
leaks.a. Loosened or damaged connecting units on
hosesRepair or replace.
b. Leakage from water pump Replace.
c. Leakage from water pipe Repair or replace.
d. Leakage around cylinder head gasket Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crank-
caseRepair or replace.
f. Damaged or cracked thermostat case Repair or replace.
g. Leakage from radiator Repair or replace.
Noisea. Defective drive belt Replace.
b. Defective radiator fan Replace.
c. Defective water pump bearing Replace water pump.
d. Defective water pump mechanical seal Replace water pump.
26
2-5[K100]DIAGNOSTICS
1. Engine Cooling System Trouble in General