Recommended Grade And Viscosity Under Severe Driving Conditions; Synthetic Oil; Cooling System - Subaru 2008 Impreza Owner's Manual

& Recommended grade and
viscosity under severe driv-
ing conditions
If the vehicle is used in desert areas, in
areas with very high temperatures, or is
used for heavy-duty applications, use of
oil with the following grade and viscosities
is recommended.
API classification SM (or SL):
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
in this 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 radia-
tor cap until the engine has been
shut off and has cooled down
completely. Since the coolant is
under pressure, you may suffer
serious burns from a spray of boil-
ing hot coolant when the cap is
removed.
CAUTION
Except WRX STI
The cooling system has been
filled at the factory with a high
quality, corrosion-inhibiting,
year-around coolant which pro-
vides protection against freezing
down to −33 F (−36 C).
SUBARU engines use aluminum
components that require the anti-
corrosive and anti-freeze proper-
ties of SUBARU Genuine Cool-
ant, which is specifically formu-
lated for the SUBARU cooling
system. Failure to use SUBARU
Genuine Coolant along with
Maintenance and service
SUBARU Cooling System Condi-
tioner at the recommended main-
tenance intervals may result in
problems, including, but not lim-
ited to shortened life of engine
components and cooling system
clogging, coolant leaks and en-
gine damage from overheating.
Problems caused by the failure to
use SUBARU Genuine Coolant
and SUBARU Cooling System
Conditioner at recommended in-
tervals are not covered under the
SUBARU Limited Warranty.
While there may be other generic
products that may provide the
required protection, they have
not been tested for compatibility
with SUBARU engines and cool-
ing system components, and
therefore they are not recom-
mended.
WRX STI
WRX STI vehicles are filled at the
factory with SUBARU Super
Coolant that does not require
the first change for 11 years/
137,500 miles (11 years/220,000
km). This coolant should not be
mixed with any other brand or
type of coolant during this peri-
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