Refrigerant: Service and Repair
Refrigerant Circuit, Servicing
HD = High-pressure end
ND = Low-pressure end
1 A/C Compressor Regulator Valve (N280)
• Do not remove.
• Check activation and function. Refer to=> [ A/C Compressor Regulator Valve (N280), Checking Switch-On Signal ] A/C Compressor Regulator Valve (N280), Checking Switch-On Signal.
• The A/C Compressor Regulator Valve (N280) is activated by the Climatronic control module (J255) , it controls pressure on the low pressure side of the refrigerant circuit. Check using Vehicle diagnosis, testing and information system (VAS5051B) in the "Guided Fault Finding".
2 A/C Compressor
• Remove A/C compressor from and reinstall onto the bracket (4 or 6 cylinder engine). Refer to=> [ A/C Compressor, Removing From Bracket ] A/C Compressor, Removing From Bracket.
• A/C Compressor, 5 cylinder, removing from and installing on bracket, engine). Refer to=> [ A/C Compressor, Removing From Bracket ] A/C Compressor, Removing From Bracket.
• A/C compressor refrigerant line, disconnecting and reconnecting, refer to => [ A/C Compressor Refrigerant Lines ] A/C Compressor Refrigerant Lines.
• When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley.
• To protect the A/C compressor, the engine should only be started with the refrigerant circuit completely assembled.
• The A/C compressor on 5 cylinder vehicles have 2 ribbed belts. The A/C compressor has a belt pulley with a double belt guide.
• Remove ribbed belt.
• A/C compressor, removing and installing, refer to => [ A/C Compressor ] A/C Compressor.
• Depending on time period of production and on engine, compressor construction type may vary. Refer to Electronic Parts Catalog (ETKA).
• At the start of production, the A/C compressors manufactured by "Denso" (type "6 SEU 14") were installed. A/C compressors from other manufacturers (for example "Sanden", type "PXE 16" or "ZJX") can be installed later.
• These A/C compressors are available as replacement parts with different oil fill capacities, therefore note capacity on A/C compressor.
• Depending on A/C compressor type, different refrigerant oil fill capacities are designated for the refrigerant circuit. The reason for the different oil capacities in the A/C compressor for an otherwise identical refrigerant circuit lies in the design of the A/C compressor itself, note these oil capacities. Too much oil in the circuit leads to higher pressures and reduces cooling performance of the system. Too little oil may lead to lubrication problems in the compressor.
• If a new compressor has been installed or new refrigerant oil has been put into the A/C compressor (for example, after blowing through the A/C system), the A/C compressor must be turned by hand approximately 10 revolutions. This ensures that the compressor is not damaged when activated.
3 Belt Pulley
• Replacing, refer to => [ A/C Compressor Belt Pulley, Replacement ] A/C Compressor Belt Pulley, Replacement.
• Ribbed belt routing, refer to Electronic Parts Catalog (ETKA).
• There is an overload protection installed between the belt pulley and the A/C compressor input shaft to protect the belt should the A/C compressor get blocked or be difficult to move.
• If the A/C compressor is runs with resistance, the overload safeguard interrupts the supply of power to it.
• Rubber elements are installed between belt pulley and A/C compressor driveshaft, vibrations which may occur during A/C compressor operation may be dissipated via these rubber elements (damper function at torque fluctuations).
• Different versions of the pulley are installed depending on the type of A/C compressor and engine. Refer to Electronic Parts Catalog (ETKA) and => [ A/C Compressor Belt Pulley, Replacement ] A/C Compressor Belt Pulley, Replacement.
• The A/C compressor on 5 cylinder vehicles have 2 ribbed belts. The A/C compressor has a belt pulley with a double belt guide.
4 Oil Drain Plug
• "Denso" A/C compressors have sealing ring installed, always replace.
• "Sanden" A/C compressors have an O-ring (8.8 mm x 1.5 mm) installed, always replace.
• "Denso" A/C compressor tightening specification 30 Nm.
• Tightening specification for the " Sanden" A/C compressor: 10 Nm
• May only be removed to drain refrigerant oil with A/C compressor removed, (rotate the A/C compressor via belt pulley to accelerate refrigerant oil flowing out).
5 Pressure Relief Valve
• Do not remove.
• Tightening specification: "Sanden"- A/C compressor 14.5 Nm, " Denso"- A/C compressor 10 Nm
• With O-ring gasket "Denso"- and " Sanden"- A/C compressors each 8.5 mm x 1.75 mm, refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.
6 Connection With Valve
• With the refrigerant circuit empty, use an adapter from the Socket for A/C Valves (T10364) to remove and install a valve insert.
The valve insert may be removed only when the refrigerant circuit is empty.
7 High Pressure Sensor (G65)
• Removing and installing, refer to => [ High Pressure Sensor (G65) ] Service and Repair.
• Checking signal, refer to=> [ High Pressure Sensor (G65), Checking Pressure Signal ] High Pressure Sensor (G65), Checking Pressure Signal.
8 Condenser
• Refrigerant lines, disconnecting and reconnecting, refer to=> [ Refrigerant Lines, Disconnecting and Connecting from Condenser ] Refrigerant Lines, Disconnecting and Connecting From Condenser.
• Condenser, removing and installing, refer to => [ Condenser ] Condenser or => [ Condenser ] Condenser.
9 Fluid Reservoir
• Fluid reservoir is secured directly onto condenser.
• Coat O-ring seals lightly with refrigerant oil before installing. Refer to=> [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.
• Replacing the O-ring seals. Refer to Electronic Parts Catalog (ETKA).
• Removing and installing, refer to => [ Fluid Reservoir ] Fluid Reservoir.
• Different versions. Refer to Electronic Parts Catalog (ETKA).
• The reservoir may be attached to or integrated in the condenser, depending on the version of the condenser. Refer to => [ Fluid Reservoir ] Fluid Reservoir and => [ Dryer Cartridge ] Description and Operation.
• A condenser will be installed in a different version on 5 cylinder engines only, as opposed to vehicles to a 4 or 6 cylinder engine. The fluids reservoir (including the dryer cartridge) installed on this condenser is a different version that is currently unavailable as a spare part. Refer to => [ Dryer Cartridge ] Description and Operation and Electronic Parts Catalog (ETKA).
• Dryer cartridge (on a condenser with an integrated fluid reservoir), removing and installing, refer to => [ Dryer Cartridge ] Description and Operation.
10 High Pressure Side Service Connection
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• To remove and install the service connection or the valve insert with the refrigerant circuit empty, use, for example, an adapter from the Socket for A/C Valves (T10364).
• Depending on engine version, it may be necessary to remove some components (for example, EVAP canister) in order to be able to connect to service coupling.
Only remove service connections when the refrigerant circuit is empty. The connection does not have a valve.
11 Sealing Cap
• With seal
• Always screw on
12 Expansion Valve
• Refrigerant lines, disconnecting and reconnecting, refer to=> [ Refrigerant Lines, Disconnecting and Connecting From Expansion Valve ] Refrigerant Lines, Disconnecting and Connecting From Expansion Valve.
• Removing and installing, refer to => [ Expansion Valve ] Expansion Valve.
• After switching off the A/C compressor in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease. This is because the expansion valve is cold and the pressure on the low pressure side increases quickly after shutting the compressor off, then the expansion valve closes and the refrigerant flows slowly to the low pressure side.
13 Evaporator
• A/C unit with evaporator, removing and installing, refer to=> [ A/C Unit ] Removal and Replacement.
• Removing and installing evaporator from heating & A/C unit, refer to=> [ Evaporator ] Evaporator.
14 Low Pressure Side Service Connection
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• To remove and install the service connection or the valve insert with the refrigerant circuit empty, use, for example, an adapter from the Socket for A/C Valves (T10364).
• Depending on engine version, it may be necessary to remove some components (for example, EVAP canister) in order to be able to connect to service coupling.
Only remove service connections when the refrigerant circuit is empty. The connection does not have a valve.
15 Sealing cap
• With seal
• Always screw on