McLaren Artura HVAC TXV Block Inspection and
Troubleshooting Guide
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Document Information
Location: Chassis / Electrical / Interior
Topic: Troubleshooting guide supporting diagnosis of potential leaks from the HVAC TXV block
Condition: N/A
Diagnostic Trouble Codes: N/A

Measure
In the event of a leak being identified at the HVAC TXV block on an Artura, there are 3 different leak possibilities
to explore.

Upper TXV leak - Leaking from above the TXV between HVAC and TXV interface.

Lower TXV/Block Interface Leak - Leaking from in between TXV and pipe block.

Residual Dye Marks / Not Cleaned - Faint residual marks, smudges, or condensate water carrying
residual dye into channels. Due to poor cleanliness during assembly or after rework.

The following procedures highlight the steps to be taken when inspecting a P16 HVAC TXV block following a
detected leak.
Using a UV torch, inspect the leak path and capture images. Please follow the respective instructions for the leak
identified on your vehicle.

Upper TXV leak
1. De-gas system noting refrigerant/oil recovered. Nominal Gas fill = 650grams ± 10grams (R1234YF)
Expected refrigerant loss rate due to system porosity = 35grams per year
2. Prior to removal, check torque value of pipe block bolt (6Nm)

Note:

3. Remove the pipes from the support clips in the tunnel as shown. Lower the block to allow for the rework
Ensure pipe assembly is of latest PN 16LA697CP

4. Inspect the black o-rings for damage and replace with new
16LA716CP: Larger Spigot: 12.5mm ID x 3mm CSD, Material:
CR
16LA717CP: Smaller Spigot: 8.92mm ID x 1.83mm CSD,
Material: CR

5. Prior to removal, check TXV bolts torque value of 6Nm is achieved

6. Remove TXV and inspect green o-rings for damage. Replace with new o-rings:
16LA621CP: 10.82mm ID X1.78mm CSD, Material: HNBR
16LA622CP: 14mm ID X1.78mm CSD, Material: HNBR

7. Check the underside of the HVAC distribution box for the presence of inserts
Care point: If the inserts are not present, please submit a Technical Request and await further guidance.

8. Wipe off/clean all residual liquids and dye from the TXV and pipe block with a dry cloth only, including all surrounding areas
toensure there are no liquids or dye present

9. Lubricate new green o-rings with PAG oil and reassemble TXV

10. Assemble TXV and torque bolts to 6Nm
Care point: If bolts do not torque up to nominal value, then it suggests an issue with the HVAC distribution box inserts. Replacement
of the HVAC distribution box will be required with part number 16LA709CP or newer
Please submit a Technical Request for parts release purposes.

11. Lubricate new black o-rings with PAG oil and assemble on to TXV

12. Reassemble pipe block and torque bolt to 6Nm

13. Thoroughly clean the block assembly and surrounding areas with solvent cleaner. Inspect again with UV light to ensure
noresidual dye is left

14. Replenish system with refrigerant and run the vehicle A/C on Quick Cool for 30 mins. Inspect for any reoccurring dye with
UVtorch. If after 30mins no dye is visible, no further action is required

Lower TXV/Block Interface Leak
1. De-gas system noting refrigerant/oil recovered. Nominal Gas fill = 650grams ± 10grams (R1234YF)
Note: Expected refrigerant loss rate due to system porosity = 35grams per year
2. Prior to removal, check torque value of pipe block bolt (6Nm)

3. Remove the pipes from the support clips in the tunnel as shown. Lower the block to allow for the rework
Ensure pipe assembly is of latest PN 16LA697CP

4. Inspect the black o-rings for damage and replace with new

16LA716CP: Larger Spigot: 12.5mm ID x 3mm CSD, Material: CR
16LA717CP: Smaller Spigot: 8.92mm ID x 1.83mm CSD, Material: CR

5. Prior to removal, check TXV bolts torque value of 6Nm is achieved
Care point: If bolts do not torque up to the nominal value, then it suggests an issue with the HVAC distribution box inserts. If the
inserts are not present, please submit a Technical Request and await further guidance.
If the inserts are present, replacement of the HVAC distribution box will be required with part number 16LA709CP or newer. Please
submit a Technical Request for parts release purposes.

6. Wipe off/clean all residual liquids and dye from the TXV and pipe block with a dry cloth only, including all surrounding areas
toensure there are no liquids or dye present
7. Reassemble pipe block and torque bolt to 6Nm

8. Thoroughly clean the block assembly and surrounding areas with solvent cleaner. Inspect again with UV light to ensure no
residualdye is left

9. Replenish system with refrigerant and run the vehicle A/C on Quick Cool for 30 mins. Inspect for any reoccurring dye with
UVtorch. If after 30 mins no dye is visible, no further action is required

Residual Dye Marks / Not Cleaned
1. Inspect thoroughly with UV torch for any potential leak paths
2. If faint marks, smudges or witness lines are visible, this suggests condensate water could have carried residual dye down the
TXVblock
Thoroughly clean the block assembly and surrounding areas with solvent cleaner. Inspect again with UV light to ensure no residual
dye is left

3. De-gas system noting refrigerant/oil recovered. Nominal Gas fill = 650grams ± 10grams (R1234YF)
Care point: Expected refrigerant loss rate due to system porosity = 35grams per year. If gas recovered equates to expected
amount then it further suggests residual marks only
4. Replenish system with refrigerant and run the vehicle A/C on Quick Cool for 30 mins. Inspect for any reoccurring dye with
UVtorch. If after 30 mins no dye is visible, no further action is required

RESTRICTED

Parts Information
16LA709CP ASSY-HVAC UNIT
16LA697CP ASSY-TUNNEL-PIPES
16LA716CP: Larger Spigot: 12.5mm ID x 3mm CSD, Material: CR
16LA717CP: Smaller Spigot: 8.92mm ID x 1.83mm CSD, Material: CR
16LA621CP: 10.82mm ID X1.78mm CSD, Material: HNBR
16LA622CP: 14mm ID X1.78mm CSD, Material: HNBR

Attachments
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This document is uncontrolled when printed. Before use, check the Knowledge Base within the
McLaren Retailer Portal to verify that this is the current version.