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Oil Separators & Vent lines

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DISPLAYING 1 to 16 (of 22 products)
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99610702652
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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

Fits:
Porsche 996 3.6L
Porsche 997 3.6L

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

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 pictrue for large parts diagram.
Diagram Ref No 1.

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99610702652
99610702651
99610702650
99610702652

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99610702652/1
Product Information
Product Information
Oil / air Separator.

Fits:
Porsche 996 3.6L
Porsche 997 3.6L

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

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.

Diagram Ref No 1.

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99610702652
99610702651
99610702650
99610702652

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99610714530
Product Information
Product Information
Breather hose, Oil separator to crankcase.

porsche

Fits:
Porsche 996 C2 / C4 / C4S 3.6L 2002-05
Porsche 997.1 C2 / C2S / C4 / C4S 3.6L 2005-08

Click 'Zoom in' for large parts diagram.
Diagram ref no 5

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99610714530
99610714530

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99610714530/1
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Breather hose, Oil separator to crankcase.

oematch

Fits:
Porsche 996 C2 / C4 / C4S 3.6L 2002-05
Porsche 997.1 C2 / C2S / C4 / C4S 3.6L 2005-08

Click 'Zoom in' for large parts diagram.
Diagram ref no 5

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99610714530
99610714530
012258
99610714530

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99610622652
Product Information
Product Information
Plastic coolant hose connector for Oil separator. Porsche 996 / 997

porsche

Fits:
Porsche 996 C2 / C4 / C4S 1998-05
Porsche 997 CARRERA 2005-08

Click 'Zoom in' for large parts diagram.
Diagram ref no 18

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99610622652
99610622651
99610622652

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99610622652PRM
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HD Aluminium construction Coolant hose connector for Oil separator.

Fits:
Porsche 996 C2 / C4 / C4S 1998-05
Porsche 997 CARRERA 2005-08

Diagram ref no 18

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99610622652PRM
99610622652
99610622651

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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
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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
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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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99610622352
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Product Information
Crankcase Housing Ventilation Hose.
Ensure reliable crankcase ventilation on your Porsche with this genuine OEM breather hose. Designed to connect the crankcase/bleed port to the PCV/intake system, this hose helps maintain correct vacuum/pressure balance, removes oil vapour efficiently and supports engine health in models such as the 911 (996 / 997.1 series).

Fits:
  • Porsche 996 C2 3.4L 1997-08/01
  • Porsche 996 C4 3.4L 1997-08/01
  • Porsche 996 C2 3.6L 09/01-2005
  • Porsche 996 C4 3.6L 09/01-2005
  • Porsche 996 C4S 3.6L 09/01-2005
  • Porsche 997 MK1 Carrera 2 3.6L 2005-08
  • Porsche 997 MK1 Carrera 4 3.6L 2005-08

Diagram Ref No 19

What This Product Does:

  • The crankcase ventilation hose provides a path for filtered crankcase gases (blow-by, vapours, oil mist) to be routed from the engine’s crankcase or oil separator back into the intake or PCV (positive crankcase ventilation) system rather than being vented uncontrolled.
  • It helps maintain correct engine vacuum/pressure balance within the crankcase, removes oil vapours, prevents buildup of excess pressure that could cause leaks or gasket failures, and supports emissions compliance.

Symptoms Of Wear Or Failure:
  • Visible cracks, splits or brittleness in the hose; rubber/engine bay hoses degrade under heat/oil/vapour over time.
  • Oil residue, grime or wetness around the hose or its connectors — if vapour is leaking, you may see oil-moisture deposit around the breather circuit.
  • Mis-fires, rough idle or engine running poorly — because un-metered air (via a damaged breather hose) may be introduced, altering the air/fuel ratio.
  • Check Engine Light (CEL) or fault codes concerning intake air leak, crankcase pressure or PCV system faults.
  • Oil smells in the engine bay / smoke from the breather area — indicating the hose may no longer be securing the vapours correctly.

Why Replacement Matters:
  • Protects engine internals & seals: Proper ventilation prevents excessive crankcase pressure which can force oil past seals or gaskets, causing leaks or damage.
  • Maintains performance & emissions: A damaged breather hose can upset engine vacuum and air-fuel mixture, affecting power, idle quality and emissions.
  • Prevents bigger failures: A failing hose is inexpensive; ignoring it could lead to more costly repairs (seal replacement, engine bay oil contamination, intake system clean-up).



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99610622352
99610622352
99610622351

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Special Order item
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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Special Order item
99951255400
Product Information
Product Information
Hose clamp, 12-22 mm - Various Applications.

porsche

Fits:
Porsche 911 - 1978 to 1989
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1998
Porsche 986 Boxster - 1997 to 2004
Porsche 996 - 1997 to 2005
Porsche 997.1 - 2005 to 2008



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99951255400
99951255400

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99951255101
Product Information
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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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99951268309
Product Information
Product Information
Oil / Air Separator Boot Clamp. 23 x 12.

porsche

Fits:
Porsche 987 Boxster 2005-08
Porsche 987C Cayman 2006-08
Porsche 996 C2 / C4 / C4S 3.6L 2002-05

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

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99951268309
99951268309

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Special Order item
99610717550
Product Information
Product Information
Replacement oil separator boot.

porsche

Fits:
Porsche 987 Boxster 2.7L / 3.2L 2005-08
Porsche 987C Cayman 2.7L / 3.4L 2005-08
Porsche 996 Carrera 3.6L 2003-05 (M96.03)
Porsche 997 Carrera 3.6L 2005-08 COUPE / CABRIO (M96.05)

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

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99610717550
99610717550

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99610717550/1
Product Information
Product Information
Replacement oil separator boot.

Fits:
Porsche 987 Boxster 2.7L / 3.2L 2005-08
Porsche 987C Cayman 2.7L / 3.4L 2005-08
Porsche 996 Carrera 3.6L 2003-05 (M96.03)
Porsche 997 Carrera 3.6L 2005-08 COUPE / CABRIO (M96.05)

Diagram Ref No 10.

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99610717550
99610717550

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DISPLAYING 1 to 16 (of 22 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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