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Oil Separators & Vent lines

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DISPLAYING 1 to 16 (of 19 products)
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99610702304/KIT2
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Oil separator. One of the most common failures in the Boxster or 996 is the Air/Oil Separator, also referred to as the AOS.

Fits: Porsche Boxster 986 2.7L , 3.2L M96.21/M96.22/M96.23/M96.24

oematch

The AOS is basically a small diaphragm distillery which distills the minute amounts of oil mist in the crankcase, liquifies it and sends it back to the crankcase. The "clean" air is now sent into the air intake (after the throttle body) to be burned off by the engine.

When the AOS starts to fail it cannot separate all of the oil out of the mist and some liquid oil is sent to the air intake.

A few drops of oil is enough to generate the GREAT SMOKE BOMB for which our cars are famous for.
A big smoke bomb once in a while is completely normal, due to the architecture of the flat-6 engine, which may let a drop of oil flow into one of the combustion chambers sporadically.

Click 'Zoom in' for large parts diagram.
Diagram Ref No 1, 4, 5, 10



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99610702304
996-107-023-04
99610702304
99610702301
99610702302
99610702303
99610723752
99610714755
996107146500

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99610702304
Product Information
Product Information
Oil separator. One of the most common failures in the Boxster or 996 is the Air/Oil Separator, also referred to as the AOS.

porsche

The AOS is basically a small diaphragm distillery which distills the minute amounts of oil mist in the crankcase, liquifies it and sends it back to the crankcase. The "clean" air is now sent into the air intake (after the throttle body) to be burned off by the engine.

When the AOS starts to fail it cannot separate all of the oil out of the mist and some liquid oil is sent to the air intake.

A few drops of oil is enough to generate the GREAT SMOKE BOMB for which our cars are famous for.
A big smoke bomb once in a while is completely normal, due to the architecture of the flat-6 engine, which may let a drop of oil flow into one of the combustion chambers sporadically.

Fits:
Porsche Boxster 986 1997-02

Click 'Zoom in' for large parts diagram.
Diagram Ref No 1.

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99610702304
99610702304
99610702301
99610702302
99610702303

The product you are viewing cross references to these numbers
99610702304/1
Product Information
Product Information
Oil separator. One of the most common failures in the Boxster or 996 is the Air/Oil Separator, also referred to as the AOS.

oematch

The AOS is basically a small diaphragm distillery which distills the minute amounts of oil mist in the crankcase, liquifies it and sends it back to the crankcase. The "clean" air is now sent into the air intake (after the throttle body) to be burned off by the engine.

When the AOS starts to fail it cannot separate all of the oil out of the mist and some liquid oil is sent to the air intake.

A few drops of oil is enough to generate the GREAT SMOKE BOMB for which our cars are famous for.
A big smoke bomb once in a while is completely normal, due to the architecture of the flat-6 engine, which may let a drop of oil flow into one of the combustion chambers sporadically.

Fits:
Porsche Boxster 986 1997-02

Click 'Zoom in' for large parts diagram.
Diagram Ref No 1.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99610702304
996-107-023-04
99610702304
99610702301
99610702302
99610702303
99610723752

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Special Order item
99610704751
Product Information
Product Information
Crankcase breather hose connector.

porsche

Fits:
Porsche Boxster 986 >>2002
Porsche 996 Carrera M >> 663 09950 Cyl 4-6

Click 'Zoom in' for large parts diagram.
Diagram ref no 6

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99610704751
99610704751
99610704750
99610714755
99610714754
99610714753

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99610714755
Product Information
Product Information
Crankcase breather hose.

porsche

Fits:
Porsche Boxster 986 >>2002
Porsche 996 Carrera M >> 663 09950 Cyl 4-6

Click 'Zoom in' for large parts diagram.
Diagram Ref No 4

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99610714755
99610714755
99610714754
99610714753

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99610714755/1
Product Information
Product Information
Crankcase breather hose.

oematch

Fits:
Porsche Boxster 986 >>2002
Porsche 996 Carrera M >> 663 09950 Cyl 4-6

Click 'Zoom in' for large parts diagram.
Diagram Ref No 4

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99610714755
99610714755
99610714754
99610714753
56088

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99610124151
Product Information
Product Information
Crankcase oil separator gasket, 1-3 cyl.

porsche

Fits:
Porsche 986 Boxster 1997-04
Porsche 987.1 Boxster 2005-08
Porsche 987C.1 Cayman 2005-08
Porsche 996 Carrera 3.4L / 3.6L 1998-05
Porsche 997.1 Carrera 3.6L / 3.8L 2005-08

Click 'Zoom in' for large parts diagram.
Diagram ref no 20

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99610124151
99610124251
99610124151
280.300

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99951255101
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Product Information
Jubilee clip 30 X 12

Fits:
Porsche 986 Boxster 1997-2004
Porsche 996 Carrera 1998-2004

Diagram Ref No 11

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99951255101
99951255100
99951255101

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99951263000
Product Information
Product Information
Oil / Air Separator Boot Clamp. 32 x 12.

porsche

Fits:
Porsche 986 Boxster 1997-04
Porsche 996 C2 / C4 3.4L 1998-01

Click pictrue for large parts diagram.
Diagram Ref No 9.

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99951263000
99951263000

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99951263000/1
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Oil / Air Separator Boot Clamp. 32 x 12.

oematch

Fits:
Porsche 986 Boxster - 1997 to 2004
Porsche 996 C2 / C4 3.4ltr - 1998 to 2001

Click 'Zoom in' for large parts diagram.
Diagram ref no 9



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99951263000
99951263000

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99610723752
Product Information
Product Information
Replacement oil separator boot.

porsche

Fits:
Porsche 996 1998-02 3.4L
Porsche Boxster 986

Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.

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Related, superseded, cross reference or alternative numbers for comparison.

99610723752
99610723752

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99610723752/1
Product Information
Product Information
Replacement oil separator boot.

oematch

Fits:
Porsche 996 1998-02 3.4L
Porsche Boxster 986

Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.

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99610723752
99610723752

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99610714600
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Product Information
Oil / Air separator pipe. 

porsche

Fits:
Porsche Boxster 986 2.7L
Porsche Boxster 986 3.2L

Diagram Ref No 5.

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99610714600
99610714600

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99610792600
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Oil separator "Motorsport". Motorsports air oil separator with dual chamber canister. This will catch all overflows from the main chamber and prevents ingestion by suction hoses. No more clouds of smoke in high speed curve!

porsche


Fits:
Porsche 996 C2 /C4 / C4S 1999-05 (not for TURBO and GT3)
Porsche 986 Boxster 2.7L / 3.2L 2000-05

Note: We recomend a new vent line 99610794700 and new hardware 90006731601 x 2.

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99610792600
99610792600

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99610708054
Product Information
Product Information
Oil separator in sump. Porsche Boxster / 996 / 997

porsche
(2 per car)

Fits:
Porsche 986 Boxster 1997-05
Porsche 987 Boxster 2.7L / 3.2L 2005-06
Porsche 996 C2 / C4 / C4S 1998-05
Porsche 997 Carrera 3.6L / 3.8L 2005-08

Click 'Zoom in' for large parts diagram.
Diagram ref no 4

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99610708054
99610708054

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99660521301
Product Information
Product Information
Purge valve oil breather cannister. 

porsche

Fits:
Porsche 986 Boxster - 1997 to 2004
Porsche 996 - 1997 to 2005
Porsche 996 turbo - 2000 to 5005

Click 'Zoom in' for large parts diagram.
Diagram ref no 9



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99660521301
99660521301

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DISPLAYING 1 to 16 (of 19 products)
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About Oil Separators & Vent lines

Oil Separators & Vent Lines – Maintain Clean Airflow and Engine Efficiency

The oil separator and vent line system plays a critical role in your Porsche’s crankcase ventilation process. By separating oil vapour from the engine’s blow-by gases, these components ensure only clean air is returned to the intake system — reducing emissions, preventing carbon build-up, and maintaining consistent engine performance.

At Design911, we stock a complete range of oil separators, breather hoses, and vent lines designed for Porsche engines of all generations. Manufactured from high-grade, heat- and oil-resistant materials, these components are built to handle the demands of high-performance driving, ensuring a tight seal, proper ventilation, and long-lasting reliability.

Whether you’re maintaining a daily-driven 911 or servicing a track-ready Cayman, our oil separators and vent lines help preserve your engine’s efficiency, longevity, and power output.

What Do Oil Separators & Vent Lines Do?

The oil separator and vent system controls crankcase pressure and removes oil vapour from the air circulating inside the engine.

Core Functions:

  • Separate oil vapour from crankcase gases, keeping intake air clean.
  • Prevent oil from entering the intake manifold or combustion chamber.
  • Maintain stable crankcase pressure for efficient engine breathing.
  • Reduce harmful emissions and extend engine life.
  • Support consistent power delivery and smooth idle performance.

By ensuring clean ventilation and stable pressure, these components protect your Porsche’s engine from oil contamination and performance loss.

Why Do Oil Separators & Vent Lines Fail?

Over time, heat cycles, oil vapours, and pressure fluctuations cause these parts to degrade or clog, leading to poor ventilation and increased oil consumption.

  • Common Causes of Failure Include:
  • Clogged internal membranes in the separator.
  • Cracked or brittle vent lines from heat and age.
  • Oil leaks from worn seals or connections.
  • Vacuum leaks, causing rough idling or poor throttle response.
  • Build-up of sludge or condensation within breather hoses.

Typical symptoms include increased oil consumption, blue exhaust smoke, rough idle, or oil leaks around the intake area, all indicating the need for inspection or replacement.

Why Replace Components?

Replacing a faulty oil separator or vent line restores proper crankcase ventilation and prevents costly engine issues like carbon build-up or oil contamination. Our precision-engineered replacements are designed for accurate fitment and long-term durability, ensuring your Porsche operates efficiently.

Key Benefits:

  • Restores clean airflow and stable crankcase pressure.
  • Reduces oil leaks and smoke from the exhaust.
  • Improves fuel efficiency and throttle response.
  • Constructed from high-quality, heat- and oil-resistant materials.
  • Direct-fit compatibility with Porsche engines.
  • Ideal for maintenance, rebuilds, or performance tuning.

Upgrading or replacing your oil separator and vent lines is essential for maintaining your Porsche’s smooth performance and clean emissions system.

Highlights:

  • High-quality Porsche oil separators, breather hoses, and vent lines.
  • Ensures clean crankcase ventilation and stable engine pressure.
  • Reduces oil leaks, smoke, and carbon build-up.
  • Durable construction for long-term reliability.
  • Direct-fit for Porsche 911, Cayman, Boxster, Panamera & more.
  • Perfect for preventive maintenance or full engine rebuilds.

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