Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

Condition
Applicable Vehicles
Model(s)

Year

Eng. Code

Trans. Code

VIN Range
From

VIN Range To

All Models

2018-2021

All

All

All

All

Revision Table
Instance Number

Published Date

Version Number

Reason For Update

2049039/8

8/7/20

87-18-08

Metadata adjustment.

2049039/7

8/6/20

87-18-08

Update to vehicle
metadata selection.
Add information to figure
15 for adaptor
VAS6338/60.

2049039/6

2/5/20

87-18-08

Update to vehicle
metadata selection.

2049039/5

11/4/19

87-18-08

Update to vehicle
metadata selection.

2049039/4

6/14/19

87-18-08

Update to vehicle
metadata selection.

2049039/3

5/28/19

87-18-08

To update special tool
part number in step 26 to
6338/48.

2049039/2

8/1/18

V871808

To include new model
year and to add tool
adaptor 6338/18.

2049039/1

11/9/17

V871713

Original publication.

Debris can be dispersed throughout the refrigerant circuit after A/C component damage. In order to
maintain A/C operating efficiency, it is important to flush the refrigerant circuit after A/C component
repairs.
Page 1 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

Note:
This bulletin must be read in its entirety before beginning repair.

Technical Background
In cases where an air conditioning system component (such as a compressor or other system
component) has failed and debris from the compressor or component is circulated throughout the
refrigerant circuit, the refrigerant circuit must be cleaned of any and all debris or damage to the
replacement components will result.
Note:
Any replacement of A/C compressors-regardless of the reason for failure must complete the AC
flush procedure to ensure the proper amount of oil is reintroduced into the refrigerant system.

Production Solution
No production change required.

Service
Tools
Use the MAHLE R1234yf A/C Service Unit VAS581005
and the R1234yf Flush Kit RTI360831040 (Figure 1).
Used for effective refrigerant handling and air
conditioning circuit flushing after air conditioning
component failure.

Figure 1. The VAS581005 Air Conditioning
Service System with Flushing Device.
Page 2 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

The VAS 6338/1 Adapter Set for Refrigerant Circuits along with an additional adapter VAS 6338/38 for
the expansion valve bypass this kit, contains the adapters necessary to complete a thorough flush
operation of a contaminated circuit.
Elsa contains the technical information for each model regarding the necessary adapter
applications and connections of the servicing station for the flush operation. See Heating,
Ventilation & Air Conditioning >> Refrigerant R1234yf-Servicing >> 00 General Technical
Data>> Refrigerant Circuit removing contaminates>> Refrigerant Circuit, Flushing with
Refrigerant R1234yf in Elsa.
All other refrigerant recovery, evacuation and recharge operations are performed using the usual
procedure specified in Elsa. An operations manual will accompany each servicing station that will
describe operation of the unit.
Procedure
Front A/C:
1. If an air conditioning component has been diagnosed as the root cause of the failure, and this
particular component has been verified to have released debris through the circuit, continue with the flush
procedure.
2. Switch the power to the servicing station ON and begin by recovering the refrigerant from the system
through the normal service fittings.
Note:
For all compressor replacements it is mandatory to flush the system of all oil in the system. The
replacement compressor comes with a full charge of oil for a complete A/C system.
Tip:
During the entire process avoid interrupting the power to the station. The station's internal memory will
keep a log of all operations and can conveniently be recalled and printed. If the power is interrupted, the
station will lose the memory of the process, and the oil volume recovered, oil volume added, refrigerant
volume recovered, etc. will have to be manually determined.
3. Disconnect the service hoses from the AC service ports of the refrigerant circuit.
The VAS 6338/1 adapters will be used to bypass the following:
 Compressor.
 Expansion Valve.
 Rear AC lines to rear AC unit (If Equipped)
 Rear AC unit Expansion Valve (If Equipped)

Page 3 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

Note:
For models with receiver drier desiccant cartridge the desiccant cartridge must be removed for the
flushing process.
For vehicles where the receiver drier is located on the condenser and DOES NOT have a remove-able
desiccant cartridge, the receiver drier must be left in the system and flushed through.
After the flush procedure is complete replace the receiver drier or drier cartridge.
4. Installing the R1234yf Flush Kit RTI360831040 flush tank to the Mahle A/C Service Unit VAS581005
5. Remove Receiver Drier. Refer to Elsa Repair Manual.
Note:
For Atlas, the front bumper does not need to be removed as stated in the Elsa repair manual.
When removing front grille ensure ignition is switched OFF and negative battery cable is
disconnected before disconnecting the front distance regulation module.
6. Remove receiver drier cartridge.
Reinstall cartridge cap with O-ring. (Figure 2)

Figure 2. Location of the Receiver Drier

Page 4 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

7. Remove expansion valve and install flush plate
VAS 6338/38. (Figure 3)

Figure 3. Installation of front expansion valve
bypass adaptor VAS 6338/38.

Note:
(Atlas Only) The rear A/C unit refrigerant lines must
be disconnected and replaced with block off
adaptors VAS 6338/5 and VAS 6338/63 before
performing the front A/C unit flush procedure.
8. (Atlas Only) Disconnect rear refrigerant lines and
install adaptors VAS 6338/5 and VAS 6338/63 as
shown. (Figure 4a, 4b)

Figure 4a. Installation of high side rear A/C Line
connection block adaptor VAS 6338/63

Page 5 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

Figure 4b. Installation of Low side rear A/C Line
connection block adaptor VAS 6338/5

9. Remove A/C Recovery machine high side
coupler from hose.
Install flush adaptor VAS 6338/48 to high side A/C
recovery machine hose. (Figure 5)
Note:
You do not have to remove low side A/C hose
coupler. The low side coupler will be connected to
the flush tank filter adaptor.

Figure 5. A.C hose adaptor 6338/44

Page 6 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

10. Disconnect AC compressor hoses from the
compressor.
Install flush adaptor VAS 6338/3 on the high side
compressor hose.
Install flush adaptor VAS 6338/12 on low side
compressor hose. (Figure 6)

Figure 6. Installation of VAS 6338/3 and 6338/12.

11. Attach high side A/C Recovery machine hose
with VAS 6338/48 fitting to low side compressor
hose adaptor VAS 6338/12. (Figure 7)

Note:
This connection strategy allows for a system flush
in the opposite direction of the normal refrigerant
flow.

Figure 7.

Page 7 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

12. Connect the low side A/C machine coupler to
the flush tank filter adaptor. (Figure 8)

Figure 8.

13. Connect flush tank hose (Yellow) to the high
side compressor hose adaptor VAS 6338/3. (Figure
9)

Figure 9.

14 Perform an extended 3 cycle flush.
15. After the flush process completes remove any adapters that were installed from the VAS 6338/1.
16. (Atlas Only) Proceed to section for cleaning the rear A/C unit. All others models continue to step 17.
17. Install a new Expansion Valve and Receiver Drier Cartridge. Reassemble all refrigerant lines.
Page 8 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

18. Print the extended flush log of the job and attach to the repair order.
19. Connect the station in the usual manner through the service fittings and perform the normal
evacuation and refrigerant recharge operations.
Note:
For Atlas a rear A/C unit flush must be performed before vacuum testing and recharging.
Atlas Rear A/C Unit
The flush process will be repeated for the additional rear air conditioning unit according to the repair
information in Elsa.
20. Lower the exhaust buy removing the rear
exhaust clamp and single rubber hanger. (Figure
10)

Figure 10.

Page 9 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

21. Remove the cross bar located in the center
under carriage area. (Figure 11)

Figure 11.

22. Remove middle heat shield from under
previously removed cross bar to access rear
expansion valve. (Figure 12)
Note:
Replace the clamping washer before reinstalling
the heat shield.

Figure 12.

Page 10 of 20
© 2020 Volkswagen Group of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and
other intellectual property rights of Volkswagen Group of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any
time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

Technical Service Bulletin

87-18-08 - Air Conditioning, Cleaning of the R1234yf Refrigerant
Circuit (U.S. Only)

Transaction
No:

2049039/8

Release date:

8/7/2020

23. Remove rear expansion valve and install
VAS6338/38 as shown. (Figure 13)

Figure 13. Location of rear air conditioning unit