2003 SUBARU IMPREZA maintenance

Maintenance and service
11-44
Abnormally low tire pressure (tread worn at
shoulders)
Rolling resistance is high, so fuel consumption is
also higher.
Abnormally high tire pressure (tread worn in
center)Ride comfort is poor. Also, the tire magnifies the
effects of road-surface bumps and dips, possibly
resulting in vehicle damage.
If the tire placard shows tire pressures for the ve-
hicle when fully loaded and for the vehicle when
towing a trailer, adjust the tire pressures to the val-
ues that match current loading conditions.

Maintenance and service
11-45
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WARNING
Driving at high speeds with excessively low tire pressures can cause the tires to deform
severely and to rapidly become hot. A sharp
increase in temperature could cause tread
separation, and destruction of the tires. The resulting loss of vehicle control could lead toan accident.
Wheel balance
Each wheel was correctly balanced when your ve-
hicle was new, but the wheels will become unbal-
anced as the tires become worn during use. Wheel
imbalance causes the steering wheel to vibrate
slightly at certain vehicle speeds and detracts fromthe vehicle ’s straight-line stability. It can also cause
steering and suspension system problems and ab-
normal tire wear. If you suspect that the wheels are
not correctly balanced, have them checked and ad-
justed by your SUBARU dealer. Also have them ad-
justed after tire repairs and after tire rotation. NOTE Loss of correct wheel alignment* causes the tires to wear on one side and reduces the ve-
hicle’ s running stability. Contact your SUBARU dealer if you notice abnormal tire wear.
* : The suspension system is designed to hold each wheel
at a certain alignment (relative to the other wheels and to
the road) for optimum straight-line stability and cornering
performance.
Wear indicators
A) New tread
B) Worn tread
1) Tread wear indicator
Each tire incorporates a tread wear indicator, which
becomes visible when the depth of the tread
grooves decreases to 0.063 in. (1.6 mm). A tire must

Maintenance and service
11-46
be replaced when the tread wear indicator appears
as a solid band across the tread.
WARNING
When a tire’s tread wear indicator becomes
visible, the tire is worn beyond the acceptable
limit and must be replaced immediately. With atire in this condition, driving at high speeds inwet weather can cause the vehicle to hydro-plane. The resulting loss of vehicle control can lead to an accident.
NOTE
For safety, inspect tire tread regularly and re-
place the tires before their tread wear indicators
become visible.
Tire rotation
Tire wear varies from wheel to wheel. To maximize
the life of each tire and ensure that the tires wear
uniformly, it is best to rotate the tires every 7,500
miles (12,500 km). Rotating the tires involves switch-
ing the front and rear tires on the right-hand side of
the vehicle and similarly switching the front and rear
tires on the left-hand side of the vehicle. (Each tire must be kept on its original side of the vehicle.)
Replace any damaged or unevenly worn tire at the
time of rotation. After tire rotation, adjust the tire
pressures and make sure the wheel nuts are cor-
rectly tightened.

Maintenance and service
11-47
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After driving approximately 600 miles (1,000 km),
check the wheel nuts again and retighten any nutthat has become loose. Tire replacement
The wheels and tires are important and integral
parts of your vehicle ’s design; they cannot be
changed arbitrarily. The tires fitted as standard
equipment are optimally matched to the characteris-
tics of the vehicle and were selected to give the best
possible combination of running performance, ride
comfort, and service life. It is essential for every tireto have a size and construction matching those
shown on the tire placard and to have a speed sym-
bol and load index matching those shown on the tire
placard.
Using tires of a non-specified size detracts from
controllability, ride comfort, braking performance,
speedometer accuracy and odometer accuracy. It
also creates incorrect body-to-tire clearances and
inappropriately changes the vehicle ’s ground clear-
ance.
All four tires must be the same in terms of manufac-
turer, brand (tread pattern), construction, and size.
You are advised to replace the tires with new ones
that are identical to those fitted as standard equip- ment.
For safe vehicle operation, SUBARU recommends
replacing all four tires at the same time. NOTE
Unidirectional tires: Some tires have a specified direction of rotation. A tire of this type has an ar-
row or other mark on its side wall to indicate thedirection of rotation. Install it so that the direc-tion of rotation is correct when the vehicle isdriven forward.

Maintenance and service
11-48
WARNING
All four tires must be the same in terms of
manufacturer, brand (tread pattern), construc-
tion, degree of wear, speed symbol, load indexand size. Mixing tires of different types, sizes or degrees of wear can result in damage to ve-
hicle’ s power train. Use of different types or
sizes of tires can also dangerously reduce
controllability and braking performance andcan lead to an accident. Use only radial tires. Do not use radial tires
together with belted bias tires and/or bias-plytires. Doing so can dangerously reduce con-
trollability, resulting in an accident.
Wheel replacement
When replacing wheels due, for example, to dam-
age, make sure the replacement wheels match the
specifications of the wheels that are fitted as stan-
dard equipment. Replacement wheels are available
from SUBARU dealers.
WARNING
Use only those wheels that are specified for your vehicle. Wheels not meeting specifica-tions could interfere with brake caliper opera-tion and may cause the tires to rub against the wheel well housing during turns. The resulting loss of vehicle control could lead to an acci-dent.

Maintenance and service
11-49
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Wheel covers
Removing the wheel cover
Insert the wheel cover remover into the notch pro-
vided, and pry the wheel cover off.
Installing the wheel cover
Align the valve with the valve hole in the cover, then fit the cover on the wheel by tapping your hand
evenly around the circumference of the cover. NOTE When any of the wheels is removed and replaced for tire rotation or to change a flat tire, always
check the tightness of the wheel nuts after driv-ing approximately 600 miles (1,000 km). If anynut is loose, tighten it to the specified torque.

Maintenance and service
11-50
Aluminum wheels (If equipped)
Aluminum wheels can be scratched and damaged
easily. Handle them carefully to maintain their ap-
pearance, performance, and safety. When any of the wheels is removed and replaced
for tire rotation or to change a flat, always check the
tightness of the wheel nuts after driving approxi-mately 600 miles (1,000 km). If any nut is loose,
tighten it to the specified torque. Never apply oil to the threaded parts, wheel nuts,
or tapered surface of the wheel. Never let the wheel rub against sharp protrusions
or curbs. Be sure to fit tire chains on uniformly and com-
pletely around the tire, otherwise the chains mayscratch the wheel. When wheel nuts, balance weights, or the center
cap is replaced, be sure to replace them with genu-
ine SUBARU parts designed for aluminum wheels. Windshield washer fluid
Check the level of the washer fluid at each fuel stop.
If the level is low, fill the fluid up to the neck of the
reservoir. Use windshield washer fluid. If windshield washer
fluid is unavailable use clean water.
In areas where water freezes in winter, use an anti-
freeze type windshield washer fluid. SUBARU Wind-
shield Washer Fluid contains 58.5% methyl alcohol
and 41.5% surfactant, by volume. Its freezing tem-
perature varies according to how much it is diluted,
as indicated below.

Maintenance and service
11-51
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Washer Fluid
ConcentrationFreezing
Temperature
30% 50%
100%10.4 °F ( –12 °C)
–4 °F ( –20 °C)
–49 °F ( –45 °C)
CAUTION
Never use engine coolant as washer fluid be-
cause it could cause paint damage. Replacement of windshield wiper blades
Grease, wax, insects, or other material on the wind-
shield or the wiper blade results in jerky wiper
operation and streaking on the glass. If you cannot
remove the streaks after operating the windshield
washer or if the wiper operation is jerky, clean the
outer surface of the windshield (or rear window) andthe wiper blades using a sponge or soft cloth with a
neutral detergent or mild-abrasive cleaner. After
cleaning, rinse the windshield and wiper blades with
clean water. The windshield is clean if beads do not
form when you rinse the windshield with water.
CAUTION
Do not clean the wiper blades with gasoline or a solvent, such as paint thinner or benzene. This will cause deterioration of the wiperblades.
If you cannot eliminate the streaking even after fol-
lowing this method, replace the wiper blades using
the following procedures:
1. Raise the wiper arm off the windshield.