b5 Ac Refrigerant Syst Serv

7/29/2019 b5 Ac Refrigerant Syst Serv

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87-161

Compressor/engine applications

Engine Manufacturer Engine code

USA/Canada

1.8L T 5V Motronic 110 KW

1.8L T 5V Motronic 110 & 125 KW

10.00: Zexel DCW-17D

10.00 : Denso 7SB-16C

AEB, ATW

AUG, AWM

2.8L V6 Motronic 142 KW Denso 7SB-16C AHA & ATQ

4.0L W8 Motronic 202 KW Denso 7SEU16 BDP


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87-162

Condensor, removing

CAUTION!

Before beginning repairs on the electrical system:

Obtain the anti-theft radio security code.

Switch the ignition off.

Disconnect the battery Ground (GND) strap.

After reconnecting battery, re-code and check

operation of anti-theft radio. Also check operation ofclock and power windows according to Repair Manualand/or Owner's Manual.

- Discharge refrigerant system Page 87-173 .

- Bring front end assembly (lock carrier) into serviceposition Repair Manual, Body Exterior, Repair Group50.

- Vehicles 10.00 : Remove front bumper carrier RepairManual, Body Exterior, Repair Group 63(10.00 )


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87-163

CAUTION!

Immediately plug open connections on A/C componentsand lines to prevent dirt and moisture contamination.

- Loosen and separate refrigerant pipes/couplings from

evaporator.

1 -Lock carrier

2 -Clip

Vehicles 10.003 -Bracket

Vehicles 10.00

4 -Grommet, upper

5 -Condensor

6 -Left air guide

7 -Right air guide

8 -Bolt

Vehicles 10.00

8 Nm (71 in lb)

Qty.: 4


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9 -Rubber grommet, lower


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87-164

Heating and A/C unit, removing and assembly

CAUTION!

Before beginning repairs on the electrical system:

Removing

Obtain the anti-theft radio security code.

Switch the ignition off.

Disconnect the battery Ground (GND) strap.

After reconnecting battery, re-code and check

operation of anti-theft radio. Also check operation ofclock and power windows according to Repair Manualand/or Owner's Manual.

- Discharge refrigerant system Page 87-173 .

- Clamp off and disconnect coolant hoses to heater coreRepair Manual, Engine Mechanical, Repair Group 19.

- Disconnect refrigerant lines to evaporator.


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87-165

CAUTION!

Immediately plug open connections on A/Ccomponents and lines to prevent dirt and moisturecontamination.

Assembly

- Remove instrument panel Repair Manual, BodyInterior, Repair Group 70.

- Loosen instrument panel cross-member Page 87-72 .

- Remove heating and A/C unit.

1 -Heater core

Always use new coolant after replacement.

2 -Housing, upper part

3 -Evaporator

Attaching inlet/outlet seal, Fig. 1

Installing seal Fig. 2

4 -Housing, lower part

With fresh/recirculating air flap

With central air flap


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87-166

Fig. 1 Evaporator inlet/outlet seal, attaching

-Evaporator inlet -B- and outlet -A- pipes must be insulated between the halves ofthe housing with seal -C-.

Fig. 2 Evaporator seal, installing

- Foam seal -B- must must be glued around circumference of evaporator -A-.

- To allow evaporator water to drain, do not attach foam seal on evaporator inarea -C-.


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87-167

A/C refrigerant system, replacingcomponents

Replacement A/C compressors, evaporators andcondensers supplied by the Parts Dept. are filledwith Nitrogen. If gas (Nitrogen) does not escapewhen component is first opened, the componentmay be faulty (leaking), do not install.

Replacement A/C compressors are filled with thetotal refrigerant oil quantity needed for the entirerefrigerant system. When an additional, rearevaporator is present, additional compressor oilmust be added after replacing the compressor.

Always replace the accumulator whenever therefrigerant system has been opened. Installimmediately after opening to prevent moisturecontamination of drier desiccant. Moreover, keeprefrigerant system and other replacementcomponents sealed for as long as possible tominimize the chance of dirt and moisturecontamination.

Always plug open refrigerant line connections toprevent dirt and moisture contamination.

If the system has been discharged due to adamaged or leaking component (refrigeranthose/line, compressor, evaporator, condenser,


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etc.), flush the refrigerant system first withcompressed air, then with nitrogen (availablelocally) and collect the oil that runs out. This willremove the refrigerant oil which may besaturated with moisture.


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87-168

CAUTION!

DO NOT flush R-134a refrigerant system withR-11. R-11 is not compatible with refrigerantR-134a and PAG oil and will cause totalsystem contamination.

If the compressor is not replaced after flushingthe system, fill compressor with the correct typeand quantity of refrigerant oil as specified under

A/C system capacities Page 87-191 . Fillcompressor with the total system oil capacity.

If the compressor is replaced, do not add anyadditional oil as the total amount of oil required isalready in the compressor.

Dispose of contaminated refrigerant oil followinglaws governing hazardous waste disposal. Donot combine any refrigerant oil with any other oldoils such as engine oil or transmission fluid.

Follow all applicable Warnings and Cautionswhen working on the A/C system.


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87-169

A/C refrigerant system pressures andtemperatures, checking

The pressures and temperatures in the A/C system will varydepending on engine speed (RPM), coolant fan speed,engine coolant temperature, A/C clutch engagement, outsidetemperature, humidity, etc.

Pressure and temperature specifications are based on thefollowing:

Engine speed (RPM) at 1500

Fresh air blower on high speed

A/C adjusted to Max. cooling

1 -Compressor, high pressure side

2 -Condenser

3 -Restrictor

4 -Evaporator

5 -Accumulator

6 -Compressor, low pressure side


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87-170

Pressure and temperature specifications

Refer to pages Page 87-169 and Page 87-133 for component identification.

Component Refrigerant state Approximate pressure (bar/psi) Approximate temperature

1 - Compressor, high pressure side Gas Up to 20 bar (290 psi) Up to 70 C (158 F)

2 - Condenser Gas

to Vapor

to Liquid

3 - Restrictor Liquid to Vapor High pressure side:

up to 20 bar (290 psi)

Low pressure side:

greater than 1.5 bar

(22 psi)1)

High pressure side:

up to 60 C (140 F)

Low pressure side:

warmer than -4 C (25 F)

4 - Evaporator Vapor to Gas Greater than 1.5 bar

(22 psi)1)

Warmer than -4 C (25 F)


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6 - Accumulator Gas

7 - Compressor, low pressure side Gas

1) Low side pressure is maintained in the refrigerant system by the variable displacement compressor despite variables intemperature, load and engine speeds (RPM).


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87-171

A/C refrigerant system, testing withpressure gauges

Due to the constant temperature/pressurerelationship of refrigerant R-134a, approximatehigh-side system temperature can be determinedbased on system pressure.

Pressure gauges may have one or moretemperature scales in addition to the pressurescale. Since various refrigerants have differenttemperature/pressure relationships, each gaugeis specific for a particular refrigerant.

Measuring pressure and temperature in a"switched-on" refrigerant system

Use the A/C refrigerant high-pressure gauge tomeasure high pressure between the compressorand restrictor (including condenser) with the A/Cswitched on.

Use the A/C refrigerant low-pressure gauge tomeasure low pressure between the restrictor and

the compressor inlet (including evaporator) withthe A/C switched on.

The temperature displays of the low- and high-pressure gauges apply only to a portion of thelow- and high-pressure sides. The low-pressure


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gauge displays approximate temperaturebetween the restrictor and evaporator outlet. Thehigh-pressure gauge displays approximatetemperature between the compressor outlet andrestrictor.


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87-172

Note:

The temperature/pressure relationship only holdstrue when the refrigerant system contains liquidand vapor, but not when it contains only gas. Inthe gaseous state, the temperature is approx. 10-

30 C (18-54 F) higher than indicated on thepressure gauge.

Measuring pressure and temperature in aclosed container or "switched-off" refrigerantsystem

Due to the constant temperature/pressurerelationship of R-12 and R-134a, approximatetemperaturein a closed container or in aswitched-off A/C system can be determinedbased on its pressure.

If the temperature displayed on a gauge is lowerthan the actual temperature of the refrigerant, therefrigerant container or system is empty(discharged).

Note:

The temperature/pressure relationship only holdstrue when the refrigerant system contains liquidand vapor, but not when it contains only gas. Inthe gaseous state, the temperature is approx. 10-


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30 C (18-54 F) higher than indicated on thepressure gauge.


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87-173

A/C refrigerant system, discharging

WARNING!

Always use an Underwriter's Laboratory (UL)approved refrigerantrecovery/recycling/recharging unit such as

Kent-Moore ACR4, or equivalent, wheneverdischarging an R-134a A/C system.

Any person who services a motor vehicle airconditioner MUST, by law, be properlytrained and certified and use approvedrefrigerant recycling equipment. Techniciansmust complete an EPA approved recyclingcourse to be certified.

State and local governments may haveadditional requirements regarding airconditioning servicing. Always comply withstate and local laws.

Always wear safety goggles when chargingor discharging system.


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87-174

CAUTION!

Always use separate refrigerantrecovery/recycling/recharging servicingequipment for R-12 and R-134a systems. DONOT use one piece of equipment for both R-12 and R-134a systems. The residual tracesof refrigerant inside the equipment willcontaminate and damage the equipment.Servicing equipment includesrecovery/recycling/recharging unit, chargingstation, vacuum pump, manifold gauges, etc.

DO NOT use R-12 servicing equipment on R-134a systems or R-134a equipment on R-12systems or damage to both the vehicle A/Csystem and servicing equipment may result.Use only equipment designed to meetSociety of Automotive Engineers (SAE)standards.

R-134a and R-12 systems use different size

service fittings. NEVER use adaptors toconvert an R-12 fitting to R-134a size or R-134a fitting to R-12 size.

Note:

Refer to safety measures starting on page


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Page 87-1 prior to discharging or charging A/Crefrigerant system.


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87-175

Note:

Make sure that initial set-up of the refrigerantrecovery/recycling/recharging unit has beencompleted before discharging the A/C system.

CAUTION!

Always follow manufacturer's instructions when using a refrigerantrecovery/recycling/recharging unit.

- Connect red high-pressure hose -A- of refrigerant recovery/recycling/rechargingunit to high side fitting on vehicle and open coupler valve.

- Connect blue low-pressure hose -B- of refrigerant recovery/recycling/rechargingunit to low side fitting on vehicle and open coupler valve.

- Following refrigerant recovery/recycling/recharging unit manufacturer'sinstructions, discharge A/C system into refrigerant recovery/recycling/rechargingunit.

- Disconnect power supply from A/C clutch to prevent accidental compressoroperation with A/C system discharged.


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A/C refrigerant system, flushing withcompressed air and nitrogen

CAUTION!

When using compressed nitrogen alwaysuse a pressure regulator and the properadaptor hoses and fittings (available locally).During flushing, use existingexhaust/ventilation systems to draw off thegas mixture escaping from the A/C system.

DO NOT flush R-134a refrigerant system withR-11. R-11 is not compatible with R-134arefrigerant and PAG oil and will cause totalsystem contamination.

Use compressed air and nitrogen (availablelocally) to remove moisture, impurities and oldrefrigerant oil from A/C refrigerant system.

First blow out old refrigerant oil and dirt withcompressed air, then dry components withnitrogen.

DO NOT blow compressed air and nitrogenthrough the compressor or expansion valve.


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Only blow compressed air and nitrogen throughdisconnected, free flowing components (i.e.disconnected hose, condenser, evaporator,etc.)

DO NOT blow compressed air and nitrogen intoa capped off A/C component. Pressurized R-134a refrigerant in the presence of oxygen mayform a combustible mixture.


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Always flush components in opposite directionof refrigerant flow.

Flush evaporator through the low-pressure linewith the high-pressure line removed.

If any component has dark thick deposits thatcannot be removed with compressed air,replace component.

Thin light gray deposits in refrigerant lines and

hoses are normal and do not impair the functionof the system.

Always replace receiver drier and restrictor afterflushing.

Dispose of contaminated refrigerant (PAG) oilfollowing laws governing hazardous wastedisposal. Do not combine PAG oil with anyother old oils such as engine oil or transmission

fluid.


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Flush refrigerant system with compressed air andnitrogen if:

Refrigerant oil is dark and viscous (thick)

Too much refrigerant oil is in the systemfollowing compressor replacement

Unclear or do not know how much refrigerant oilis in the system

Moisture, dirt or other impurities have enteredthe refrigerant system (i.e. following anaccident)

Unable to pull a constant vacuum duringevacuation of a leak-free system due toexcessive moisture in the system

Refrigerant system has been open longer thanthe time required for normal repairs (i.e.following an accident)

Based on temperature and pressuremeasurements, system is diagnosed withmoisture contamination


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Compressor is replaced due to noises orinternal damage

Flushing is required after replacing certaincomponents in certain situations Page 87-167


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87-179

A/C refrigerant system, evacuating andrecharging

WARNING!

Always use an Underwriter's Laboratory (UL)approved refrigerant recovery/recycling/recharging unit such as Kent-

Moore ACR4, or equivalent, when evacuatingand recharging an R-134a A/C system.

Any person who services a motor vehicle air

conditioner MUST, by law, be properlytrained and certified and use approvedrefrigerant recycling equipment. Techniciansmust complete an EPA approved recyclingcourse to be certified.

State and local governments may haveadditional requirements regarding airconditioning servicing. Always comply withstate and local laws.

Always wear safety goggles whendischarging, evacuating and recharging anA/C system.


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CAUTION!

Always follow manufacturer's instructionswhen using a refrigerantrecovery/recycling/recharging unit.


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Notes:

Refer to R-134a safety measures starting onpage prior to discharging or charging A/Crefrigerant system.

Follow refrigerant recovery/recycling/rechargingunit manufacturer's instructions for evacuatingand recharging A/C system.

Evacuate refrigerant system for a minimum of30 minutes.

When recharging A/C system, add correctamount of refrigerant and PAG oil to systemPage 87-191 .

After system recharge, manually rotate A/Ccompressor approx. 10 turns before startingengine. Start engine with A/C OFF. After idlespeed has stabilized, switch A/C ON and let

engine idle (compressor running) for a minimumof two minutes before raising engine speed.

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b5 Ac Refrigerant Syst Serv