Service

Technical Information

174/23 ENU

8734

Little or No Cooling Power from the Air-Conditioning System: Checking Refrigerant Lines on
Air-Conditioning Compressor (174/23)

8

Change Overview

Model Line:

Version

Date

Change

0

11/29/2023

•

First Publication

1

01/27/2026

•

Update of Order Types and
MY

Panamera (971 / YAA / YAB)
Cayenne (9YA / 9YB)

Model Year:

As of 2019

Equipment:

Without alternative drive system (M-No. 0K0)

Concerns:

Air-conditioning compressor

Information:

Customers complain that the air-conditioning system cooling performance is too low. Drop formation of
refrigerant compressor oil is detected at the low point of the air-conditioning compressor housing. ⇒ Drop
formation on air-conditioning compressor

Drop formation on air-conditioning compressor

AfterSales

Jan 27, 2026
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8

Service
8734

ENU

Technical Information

174/23

Insufficient sealing of the refrigerant lines on the air-conditioning compressor can lead to a leak in the air-conditioning
system.
This leak can be caused by a twisted O-ring ⇒ Twisted
O-ring installed in conjunction with the design-related burr
Þ Twisted O-ring -1- or by a damaged O-ring
on the O-ring ⇒
on the refrigerant line.
As a result, refrigerant compressor oil can leak and collect
at the flange of the refrigerant line and at the lowest point of
the air-conditioning compressor.

Cause:

Twisted O-ring
Action:

If there is a complaint, check the respective O-ring of the affected refrigerant line and replace it if necessary.

Installation
Position:

Installation location for air-conditioning compressor / refrigerant lines (shown on the Porsche Cayenne)

Jan 27, 2026
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AfterSales

Service

Technical Information

174/23 ENU

8734

8

Required parts and materials
Parts Info:

Part No.

Designation
– Location

Number

N 10414402

⇒ Cheese head bolt with multiple-tooth head M8 x 28
– Refrigerant line to compressor

1 piece

95557374903

⇒ O-ring, 23.8 x 2.4
– Refrigerant line between compressor and evaporator

1 piece

or
Only for Panamera (971)
99970755741

⇒ O-ring 11.00 x 2.50 NX
– Refrigerant line between compressor and condenser

1 piece

or
Only for Cayenne (9YA / 9YB)
95557374901

⇒ O-ring, 11,0 x 2.5
– Refrigerant line between compressor and condenser

1 piece

Additional parts required for Cayenne (9YA / 9YB) with Porsche Dynamic Chassis Control (PDCC)
(M-No. 1P7)
PAF00072900

⇒ Hexagon socket head bolt, M8 x 20
– Front section of front underbody cover

3 pieces

or
Additional parts required for Cayenne (9YA / 9YB) with engine protective plate (M-No. 1SF)
N 10082912

Materials:

⇒ Hexagon screw (instrument cluster), self-locking
M6 x 16
– Front engine protection on holder

3 pieces

Required materials (usually already available in the Porsche Center)
Part No.

Designation
– Location

Quantity

Vehicles with refrigerant R1234yf

AfterSales

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8

Service
8734

ENU

Technical Information

174/23

9A757390010

⇒ Refrigerant compressor oil 1234yf
– Air-conditioning system

As required

....

⇒ Refrigerant 1234yf
– Air-conditioning system

As required

Vehicles with refrigerant R134a
00004330579

⇒ Refrigerant compressor oil R134a
– Air-conditioning system

As required

....

⇒ Refrigerant R134a
– Air-conditioning system

As required

Required tools
Tools:

•
•
•
•
•
•

P90999 - Porsche Tester 4
Battery charger with a current rating of at least 90 A and a current and voltage-controlled charge map
for lithium starter batteries, e.g. battery charger 90 A.VAS 5908 - battery charger 90 A
Torque wrench, 2-10 Nm (1.5-7.5 ftlb.), e.g., V.A.G 1783 - Torque wrench, 2-10 Nm (1.5-7.5 ftlb.)
Torque wrench, 20-100 Nm (15-74 ftlb.), e.g., VAS 5820 - Torque wrench, 20-100 Nm (15-74 ftlb.)
Air conditioning service unit for R1234yf, e.g., VAS 581 001A - air-conditioning service unit R1234yf
or air conditioning service unit for R134a, e.g., VAS 6746A - air-conditioning service station R134a
VAS 6122 - Engine plug set

Checking refrigerant compressor oil loss
Work Procedure: 1

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Remove front underbody cover.

⇒ Workshop Manual '519219 Removing and installing cover for front underbody cover'

2

Remove front left wheel housing liner.
For procedure, see: ⇒ Workshop Manual '505619 Removing and installing wheel housing liner front'

3

Check and evaluate refrigerant compressor oil loss on the flange of the refrigerant line for the
compressor - evaporator and refrigerant line for the compressor - condenser on the air-conditioning
compressor. ⇒ Oil loss on air-conditioning compressor

AfterSales

Service

Technical Information

174/23 ENU

8734

8

Oil loss on air-conditioning compressor
Assessment
( )

✗)
(✗

Action

No refrigerant compressor oil loss can be
Þ Oil loss on air-condidetected on flange ⇒
tioning compressor -1- or air-conditioning
Þ Oil loss on air-conditioning
compressor ⇒
compressor -2-.
Refrigerant compressor oil loss can be detected
Þ Oil loss on air-conditioning
on flange ⇒
compressor -1- or air-conditioning compressor
Þ Oil loss on air-conditioning compressor -2-.
⇒
⇒ Flange refrigerant line leak

AfterSales

Locate the complaint elsewhere.
End of test.
Continue with:
⇒ Technical Information '505619 Follow-up
actions'
Replace the O-ring of the affected refrigerant
line.
Continue with:
⇒ Technical Information '505619 Replacing
O-ring refrigerant line on air-conditioning

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8734

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Technical Information

174/23

compressor'

Flange refrigerant line leak

Replacing O-ring refrigerant line on air-conditioning compressor
Work Procedure: 1

Replace the O-ring of the affected refrigerant line on the air-conditioning compressor.
For procedure, see:
⇒ Workshop Manual '874319 Removing and installing refrigerant line between compressor and
condenser'
⇒ Workshop Manual '874519 Removing and installing compressor/evaporator line (section from
air-conditioning compressor to internal heat exchanger)'

Follow-up actions
Work Procedure: 1
2

Install the front left wheel housing liner.
For procedure, see: ⇒ Workshop Manual '505619 Removing and installing wheel housing liner front'
Install front underbody panelling.

⇒ Workshop Manual '519219 Removing and installing cover for front underbody cover'

Working position and PCSS encryption (Panamera)
Labor position:
APOS

Labor operation

I No.

87450100

Checking refrigerant compressor oil loss

87454910

Replacing O-ring refrigerant line on air-conditioning
compressor
PCSS encryption:

Location (FES5)

87340

Air-conditioning compressor

Damage type (SA4)

5000

Leaks

Jan 27, 2026
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AfterSales

Service

Technical Information

174/23 ENU

8734

8

Working position and PCSS encryption (Cayenne)
Labor position:
APOS

Labor operation

I No.

87450100

Checking refrigerant compressor oil loss

87454900

Replacing O-ring refrigerant line on air-conditioning
compressor
PCSS encryption:

Location (FES5)

87340

Air-conditioning compressor

Damage type (SA4)

5000

Leaks

Important Notice: Technical Bulletins issued by Porsche Cars North America, Inc. are intended only for use by professional automotive technicians who have attended Porsche service training courses. They are
written to inform those technicians of conditions that may occur on some Porsche vehicles, or to provide information that could assist in the proper servicing of a vehicle. Porsche special tools may be necessary in
order to perform certain operations identified in these bulletins. Use of tools and procedures other than those Porsche recommends in these bulletins may be detrimental to the safe operation of your vehicle, and
may endanger the people working on it. Properly trained Porsche technicians have the equipment, tools, safety instructions, and know-how to do the job properly and safely. Part numbers listed in these bulletins
are for reference only. The work procedures updated electronically in the Porsche PIWIS diagnostic and testing device take precedence and, in the event of a discrepancy, the work procedures in the PIWIS Tester
are the ones that must be followed.

© 2026 Porsche Cars North America, Inc.

AfterSales

Jan 27, 2026
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