2003 SUBARU IMPREZA WRX Owners Manual

Maintenance and service
11-14
New API Certification Mark (Starburst Mark)
In choosing an oil, you want the proper quality and
viscosity, as well as one that will add to fuel econo-
my. The following table lists the recommended vis-
cosities and applicable temperatures.
When adding oil, different brands may be used to-
gether as long as they are the same API classifica-
tion and SAE viscosity as those recommended bySUBARU.SAE viscosity number and applicable temperature
*) 5W-30 is preferred.
Engine oil viscosity (thickness) affects fuel economy.
Oils of lower viscosity provide better fuel economy.
However, in hot weather, oil of higher viscosity is re-
quired to properly lubricate the engine.
CAUTION
Use only engine oil with the recommended
grade and viscosity.

Maintenance and service
11-15
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Recommended grade and viscosity under severe driving conditions
If the vehicle is used in desert areas, in areas with
very high temperatures, or used for heavy-duty ap-
plications such as towing a trailer, use of oil with the
following grade and viscosities is recommended.
API classification SL or SJ: SAE viscosity No.: 30, 40, 10W-50, 20W-40,
20W-50
Synthetic oil
You can use synthetic engine oil that meets the
same requirements given for conventional engine
oil. When using synthetic oil, you must use oil of the
same classification, viscosity and grade shown inthis owner ’s manual, and must follow the oil and filter
changing intervals shown in the maintenance schedule. Cooling system
WARNING
Never attempt to remove the radiator cap until the engine has been shut off and has cooled
down completely. Since the coolant is underpressure, you may suffer serious burns from a
spray of boiling hot coolant when the cap isremoved.
CAUTION

The cooling system has been filled at the
factory with a high quality, corrosion-inhibit-
ing, year-around coolant which provides protection against freezing down to –33°F
(–36 °C). For adding, use genuine SUBARU
coolant or an equivalent: a mixture of 50%
soft water and 50% ethylene-glycol basis cool-
ant. Use of improper coolants may result in
corrosion in the cooling system. It is impor- tant to maintain protection against freezing and corrosion, even if freezing temperaturesare not expected. Never mix different kinds ofcoolant.

Maintenance and service
11-16
Do not splash the engine coolant over
painted parts. The alcohol contained in the en- gine coolant may damage the paint surface.
Cooling fan, hose and connections
Your vehicle employs an electric cooling fan which
is thermostatically controlled to operate when the
engine coolant reaches a specific temperature.If the radiator cooling fan does not operate even
when the engine coolant temperature gauge ex-
ceeds the normal operating range, the cooling fan
circuit may be defective. Check the fuse and re-
place it if necessary. If the fuse is not blown, havethe cooling system checked by your SUBARU deal-
er.
If frequent addition of coolant is necessary, there
may be a leak in the engine cooling system. It is rec-
ommended that the cooling system and connectionsbe checked for leaks, damage, or looseness.
Engine coolant
Checking the coolant level
1) “FULL” level mark
2) “LOW” level mark
Check the coolant level at each fuel stop.
1. Check the coolant level on the outside of the res-ervoir while the engine is cool.
2. If the level is close to or lower than the “LOW”
level mark, add coolant up to the “FULL” level mark.
If the reserve tank is empty, remove the radiator cap
and refill as required.

Maintenance and service
11-17
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1) Rubber gaskets
3. After refilling the reserve tank and the radiator, re- install the caps and check that the rubber gaskets
inside the radiator cap are in the proper position.
CAUTION
Be careful not to spill engine coolant when
adding it. If coolant touches the exhaust pipe, it may cause a bad smell, smoke, and/or a fire. Do not splash the engine coolant over
painted parts. The alcohol contained in the en-gine coolant may damage the paint surface.
Changing the coolant
1) Drain plug
Change the engine coolant using the following pro-
cedures according to the maintenance schedule.
1. Remove the under cover.
2. Place a proper container under the drain plugand loosen the drain plug.
3. Loosen the radiator cap to drain the coolant from
the radiator. Then drain the coolant from the reserve
tank. Tighten the drain plug securely.

Maintenance and service
11-18
WARNING
Never attempt to remove the radiator cap until the engine has been shut off and has cooled
down completely. Since the coolant is underpressure, you may suffer serious burns from a
spray of boiling hot coolant when the cap is removed.
4. Install the under cover.
Non-turbo models
1) Filler neck
2) Fill up to this level
Turbo models
1) Filler neck
2) Fill up to this level
5. Slowly pour the coolant and fill to the radiator fill-
er neck. Do not pour the coolant too quickly, as this
may lead to insufficient air bleeding and trapped airin the system.

Maintenance and service
11-19
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Guideline of coolant quantity (including coolant in reser- voir tank):
Non-turbo models: MT. 7.4 US qt (7.0 liters, 6.2 Imp qt)
AT. 7.3 US qt (6.9 liters, 6.1 Imp qt)
Turbo models: MT. 8.1 US qt (7.7 liters, 6.8 Imp qt)
AT. 8.0 US qt (7.6 liters, 6.7 Imp qt)
1) “FULL” level mark
2) “LOW” level mark
CAUTION
Be careful not to spill engine coolant when
adding it. If coolant touches the exhaust pipe, it may cause a bad smell, smoke, and/or a fire. Do not splash the engine coolant over
painted parts. The alcohol contained in the en-gine coolant may damage the paint surface.
6. Pour the coolant and fill to the reservoir tank ’s
“FULL” level mark.
1) Rubber gaskets
7. Put the radiator cap back on and tighten firmly. At

Maintenance and service
11-20
this time, make sure that the rubber gasket in the ra-
diator cap is correctly in place.
8. Start and run the engine for more than five min-utes at 2,000 to 3,000 rpm.
9. Stop the engine and wait until the coolant coolsdown (122 to 140°F [50 to 60 °C]). If there is any loss
of coolant, add coolant to the radiator ’s filler neck
and to the reserve tank ’s “FULL” level.
10. Put the radiator cap and reservoir cap back on
and tighten firmly. Air cleaner element
The air cleaner element functions as a filter screen.
When the element is perforated or removed, engine
wear will be excessive and engine life shortened.
The air cleaner element is a viscous type. It is un-
necessary to clean or wash the element.
WARNING
Do not operate the engine with the air cleaner
element removed. The air cleaner element notonly filters intake air but also stops flames ifthe engine backfires. If the air cleaner elementis not installed when the engine backfires, youcould be burned.
Replacing the air cleaner element
Non-turbo models
Replace the air cleaner element according to the
maintenance schedule in the “Warranty and Mainte-
nance Booklet ”. Under extremely dusty conditions,
replace it more frequently. It is recommended that
you always use genuine SUBARU parts.

Maintenance and service
11-21
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1) Bolt
1. Remove the bolt securing the rear air cleaner ele-
ment case.
2. Unsnap the three clamps holding the rear air
cleaner element case.1) Air cleaner element
3. Separate the rear air cleaner element case from
the front cleaner element case and remove the air
cleaner element.
4. Clean the inside of the front and rear air cleaner
element cases with a damp cloth and install a new air cleaner element.
5. Insert the four projections on the rear air cleaner
element case into the slits on the front air cleaner
element case and snap the three clamps on the rearair cleaner element case and then tighten the bolt.