A/C Refrigerant System, Servicing
A/C Refrigerant System, Servicing
NOTE
- Before carrying out any work on the A/C refrigerant system, refer to all CAUTIONS and WARNINGS in A/C refrigerant system safety measures.
- Service refrigerant system using Kent More ACR4 or equivalent
- Only system components identified with an * can be serviced or replaced without discharging refrigerant system.
- During servicing, all couplings, fittings and related fasteners must be torqued to specifications.
1 - Refrigerant hose
- Between accumulator and compressor
2 - Coupling
- Thread Pi 28 mm; pitch 1.5 mm
- 40 Nm (30 ft lb)
3 - O-ring
- 17.2 mm; 1.8 mm
4 - Refrigerant hose
- Between evaporator and condensor
5 - Coupling
- Thread Pi 20 mm; pitch 1.5 mm
- 15 Nm (11 ft lb)
6 - O-ring
- 10.8 mm; 1.8 mm
7 - Restrictor
- Removing and installing See Fig. 1
8 - O-ring
- 7.5 mm; 1.5 mm
9 - O-ring
- 10.8 mm; 1.8 mm
10 - High pressure service valve
- Only use Kent Moore ACR4 or equivalent.
- Removing and installing See Fig. 2
11 - Cap*
12 - O-ring
- 10.8 mm; 1.8 mm
13 - O-ring
- 17.2 mm; 1.8 mm
14 - Evaporator
- In heater/evaporator unit
15 - Hex socket bolt(s)
- At evaporator coupling
- 10 Nm (7 ft lb)
16 - Cap*
17 - Low pressure service valve
- Only use kent Moore ACR4 or equivalent.
- Removing See Fig. 3
18 - O-ring
- 7.6 mm; 1.8 mm
19 - Refrigerant hose
- Between evaporator and accumulator
20 - Manifold bolts
- 25 Nm (18ft lb)
21 - O-ring
- Compressor inlet
- 11.1 mm; 1.8 mm
22 - O-ring
- Compressor outlet
- 23.8 mm; 2.4 mm
23 - Compressor
- With A/C clutch -N25-
- Zexel DCW 17D
24 - Pressure relief valve
- Checking, Zexel compressor (4-cylinder engine) See Fig.6
- Checking, Denso compressor (6-cylinder engine) See Fig.7
25 - Compressor
- With A/C clutch -N25-
- Denso 7SB- 16C
26 - O-ring
- Compressor outlet
- 23.8 mm; 2.4 mm
27 - O-ring
- Compressor inlet
- 11.1 mm; 1.8 mm
28 - Manifold bolts
- 25 Nm (18 ft lb)
29 - A/C clutch -N25-
30 - Condenser
31 - Coupling
- Thread Pi 20 mm; pitch 1.5 mm
32 - Coupling
- Thread Pi 24 mm; pitch 1.5 mm
33 - O-ring
- 14 mm; 1.8 mm
34 - Coupling
- Thread Pi 24 mm; pitch 1.5 mm
35 - O-ring
- 10.8 mm; 1.8 mm
36 - Refrigerant pipe
- Between compressor and condensor
37 - Coupling
- Thread Pi 20 mm; pitch 1.5 mm
38 - O-ring
- 7.6 mm; 1.8 mm
39 - A/C pressure switch -F129-*
- Can be removed without discharging refrigerant system.
- Checking See Fig.4
- Replacing See Fig.5
- Inspect O-ring for damage and proper seating in recess of switch before installation.
- 8 Nm (71 in lb)
40 - Accumulator
- Always replace whenever refrigerant system has been opened
41 - Coupling
- Thread Pi 28 mm; pitch 1.5 mm
42 - O-ring
- 17.2 mm; 1.8 mm
Fig. 1 Restrictor, removing and installing
Removing
- Discharge refrigerant system.
- Loosen and separate coupling -A- on evaporator inlet pipe.
- Tightening torque 15 Nm (11 ft lb)
- Replace O-ring -D-
- O-ring -D- = 10.7 mm, 1.8 mm
- Remove restrictor -B- using long nose pliers
CAUTION!
Immediately plug open connections on A/C components and lines to prevent dirt and moisture contamination.
Installing
- Insert restrictor -B- into evaporator inlet pipe with arrow pointing in direction of refrigerant flow (towards evaporator).
NOTE:
- Ensure proper positioning of O-ring -C-
- Restrictor must fit tight in inlet pipe (push in as far as it will go)
- Assemble to allow stress free mounting of evaporator pipes
Fig. 2 High pressure service valve, removing
- Discharge refrigerant system.
- Unscrew and remove high pressure service valve -3-.
1 - Connection with internal thread
2 - O-ring, 10.8 mm; 1.8 mm
3 - High pressure service valve, with groove for O-ring and internal thread for cap
4 - O-ring, 10.8 mm; 1.8 mm
5 - Cap
Fig. 3 Low pressure service valve, removing
- Discharge refrigerant system.
- Unscrew and remove low pressure service valve -3-.
1 - Connection with external thread and groove for O-ring
2 - O-ring, 7.6 mm; 1.8 mm
3 - Low pressure service valve
4 - O-ring, 7.6 mm; 1.8 mm
5 - Cap
Fig. 4 A/C pressure switch -F129-, checking
- The pressure switch can be removed without discharging refrigerant system.
- Visually check that O-ring 10.8 mm x 1.8 mm is positioned correctly in the groove.
Function
Switch part between terminals 1 and 2 switches off the A/C clutch -N25- when the system pressure is too high or when there is not enough refrigerant in the system
- Switch opens when the pressure is below 1.2 bar and closes again above 2.4 bar (switch point).
- Switch opens above 32 bar and closes again below 24 bar (switch point).
Switch part between terminals 3 and 4 switches coolant fan -V7- (via the coolant fan control module -J293-) to the next higher fan speed when system pressures increase.
- Switch closes above 16 bar and opens again below 12.5 bar (switch point).
Checking:
- With the engine running, briefly bridge terminal 1 and 2 of connector. If the A/C clutch -N25- engages, the refrigerant circuit is empty.
-F129- functional checks
To determine proper A/C system performance, perform the following functional checks with the switch installed and connected.
- Check refrigerant capacity (fill). If system pressure is too low (refrigerant leakage), -F129- switches A/C clutch off.
- Check cooling fan function. When system pressure increases, -F129- causes coolant fan -V7- to switch to next higher fan speed.
- Check if A/C system switches off. At excessive system pressures (e.g.: caused by high ambient temperatures or if condensor is blocked), -F129- switches A/C clutch off.
Fig. 5 A/C pressure switch -F129-, replacing
1 - Electrical connector
2 - A/C pressure switch -F129- (8 Nm)
3 - Hex (to counter-hold)
4 - Condenser connection
5 - Lock carrier
6 - Cover
- Remove right headlight
- Remove bolt -arrow- (below cover -6-) between lock carrier -5- and cover -6-.
- Disconnect electrical connector -1-.
To prevent damage to condenser pipe connection -4- counter-hold hex fitting -3- with appropriate wrench when loosening switch.
- Remove A/C pressure switch -2-.
Fig. 6 Pressure relief valve - Zexel compressor, checking
- Function: Protects refrigerant circuit from over-pressure.
- Refrigerant oil deposited on rear of compressor indicates pressure relief valve has opened to release pressure -arrow-. An adhesive plate is pushed out.
Fig. 7 Pressure relief valve - Denso compressor, checking (6-cyl. engines)
- Function: Protects refrigerant circuit from over-pressure.
- Refrigerant oil deposited in area of compressor manifold indicates pressure relief valve has opened to release pressure - arrow-. An adhesive plate is pushed out.