Subaru Legacy IV (2008 year). Manual - part 978

AC-15

General Description

HVAC SYSTEM (HEATER, VENTILATOR AND A/C)

C: CAUTION

1. HFC-134A A/C SYSTEM

• The cooling system components for the HFC-
134a system such as the refrigerant and compres-
sor oil are different from the conventional CFC-12
system components and they are incompatible with
each other.
• Vehicles with the HFC-134a system can be iden-
tified by the label (A) attached to the vehicle.
Before maintenance, check which A/C system is in-
stalled to the vehicle.

2. COMPRESSOR OIL

• HFC-134a compressor oil has no compatibility
with that of CFC-12 system.
• Use only Denso Oil 8, the manufacturer-autho-
rized compressor oil for the HFC-134a system.
• Do not mix multiple compressor oils.
If CFC-12 compressor oil is used in the HFC-134a
A/C system, the compressor may become stuck
due to poor lubrication, or the refrigerant may leak
due to swelling of rubber parts.
On the other hand, if HFC-134a compressor oil is
used in a CFC-12 A/C system, the durability of the
A/C system will be lowered.
• HFC-134a compressor oil is very hygroscopic.
When replacing or installing/removing A/C parts,
immediately isolate the oil from atmosphere using a
plug or tape. In order to avoid moisture, store the oil
in a container with its cap tightly closed.

3. REFRIGERANT

• CFC-12 refrigerant cannot be used in a HFC-
134a A/C system. HFC-134a refrigerant, also can-
not be used in a CFC-12 A/C system.
• If an incorrect or no refrigerant is used, it will re-
sult in poor lubrication and the compressor itself
may be damaged.

4. HANDLING OF REFRIGERANT

• The refrigerant boils at approx. –30°C (–22°F).
When handling it, be sure to wear protective gog-
gles and protective gloves. Direct contact of the re-
frigerant with skin may cause frostbite.
If the refrigerant gets into your eye, avoid rubbing
your eyes with your hands. Wash your eye with
plenty of water, and receive medical treatment from
an eye doctor.
• Do not heat a service can. If a service can is di-
rectly heated, or put into boiling water, the inside
pressure will become extremely high. This may
cause the can to explode. If a service can must be
warmed up, use warm water of 40°C (104°F) or
less.
• Do not drop or impact a service can. (Observe
the precautions and operation procedure described
on the refrigerant can.)
• When the engine is running, do not open the
high-pressure valve of the manifold gauge. High-
pressure gas can back-flow resulting in an explo-
sion of the can.
• Provide good ventilation and do not work in a
closed area.

• In order to prevent global warming, avoid releas-
ing HFC-134a into the atmosphere. Using a refrig-
erant recovery system, discharge and recycle the
gas.

AC-00762

(A)

AC-16

General Description

HVAC SYSTEM (HEATER, VENTILATOR AND A/C)

5. O-RING CONNECTIONS

• Always use a new O-ring.
• In order to keep the O-rings free of lint which can
cause a refrigerant gas leak, perform operations
without gloves and cloth.
• Apply compressor oil to O-rings to avoid sticking,
before installation.
• Use a torque wrench to tighten the O-ring fittings.
Over-tightening will result in damage of the O-ring
and deformation of the pipe end.
• If the work is interrupted before completing pipe
connections, recap the pipes, components and fit-
tings with a plug or tape to prevent foreign matter
from entering.

• Visually check the surfaces and mating surfaces
of O-rings, threads and connecting points. If a fail-
ure is found, replace the applicable parts.
• Install the O-rings straight against the pipe
groove.

(A) Goggles

(B) Gloves

(C) Avoid open flame

(D) No direct heat on container

(E) Do not discharge

(F) Loosen

(A)

(B)

(C)

(D)

(E)

(F)

AC-00007

(A) Seal

(A) O-ring

(B) OK

(C) NG

(D) Groove

(A)

AC-00008

AC-00009

(D)

(B)

(C)

(C)

(A)

AC-17

General Description

HVAC SYSTEM (HEATER, VENTILATOR AND A/C)

• Use compressor oil specified in the service man-
ual to lubricate the O-rings.
Apply oil to the top and sides of O-rings before in-
stallation.
Apply compressor oil to the pipe grooves.

• After tightening, use a clean cloth to remove ex-
cess compressor oil from the connections and any
oil which may have run on the vehicle body or other
parts.
• If any leakage is suspected after tightening, do
not tighten the connections further, but disconnect
the connections, remove the O-rings, and check
the O-rings, threads, and connections.

AC-00010

AC-18

General Description

HVAC SYSTEM (HEATER, VENTILATOR AND A/C)

D: PREPARATION TOOL

CAUTION:
When working on vehicles with a HFC-134a system, only use HFC-134a specified tools and parts. Do
not mix CFC-12 tools and parts. If HFC-134a and CFC-12 refrigerant or compressor oil is mixed, it will
result in poor lubrication and the compressor itself may be damaged.
In order to prevent the mixture of HFC-134a and CFC-12 parts and liquid, the tool and screw type and
the type of service valves used are different. The gas leak detectors for the HFC-134a and CFC-12
systems must also not be interchanged.

 HFC-134a

CFC-12

Tool & screw type

Millimeter size

Inch size

Valve type

Quick joint type

Screw-in type

ILLUSTRATION

Tools and Equipment

Wrench

Various WRENCHES will be required to service any A/C system. 7 to 
40 N·m (0.7 to 4.1 kgf-m, 5 to 30 ft-lb) torque wrench and various crow-
foot wrenches will be needed. Open end or flare nut wrenches will be 
needed to affix the pipe and hose fittings.

Applicator bottle

A small APPLICATOR BOTTLE is recommended to apply compressor 
oil to the various parts. It can be available at a hardware or drug store.

Manifold gauge set

A MANIFOLD GAUGE SET (with hoses) is available either from a 
refrigerant supplier or an automotive equipment supplier.

AC-00213

AC-00012

AC-00013