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Porsche // Boxster 986/987/981 (1997-2016) // Any
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- Porsche 955 Cayenne Turbo 4.5L 2003-06
Vent line from valve cover to crankcase
Vent line from the valve cover to the crankcase by OE Match for the Porsche 955 Cayenne Turbo 4.5L from 2003–06. This replacement line forms part of the M48.50 engine crankcase ventilation system.
Fits:
Porsche 955 Cayenne Turbo 4.5L 2003 - 2006
Diagram ref no 12
What This Product Does
The vent line provides a route between the valve cover and crankcase, allowing crankcase gases to move through the engine ventilation system. Correct ventilation helps manage crankcase pressure and limits the escape of oil mist around damaged or poorly sealed connections.
Functions
- Routes crankcase gases through the ventilation system
- Connects the valve cover and crankcase ventilation circuit
- Helps maintain controlled crankcase pressure
- Supports the management of oil vapour within the breather system
Technical Details
- Brand: OE Match
- Part type: valve cover-to-crankcase vent line
- OE reference: 94810721552
- Engine application: M48.50 4.5L V8
- Assembly: valve cover and engine cover
- Diagram ref no 12
Symptoms of Fault
- Cracks or brittleness in the existing vent line
- Oil mist or seepage around the hose connections
- Whistling or unusual noises from the crankcase area
- Rough or unstable idle caused by an air leak
- Increased oil consumption or smoke
- Abnormal crankcase vacuum
Why Replacement Matters
Age, engine heat and repeated pressure cycles can cause a breather line to harden, split or lose its seal. Replacing a damaged line helps restore the intended ventilation route and reduces the risk of vacuum leaks, oil residue and unstable crankcase pressure. Inspect adjoining seals, fittings and breather components during installation, as deterioration elsewhere in the system can produce similar symptoms.
OE Reference
- 94810721552
FAQs
- Does smoke always indicate a failed vent line? No. Smoke can also be associated with the oil separator, an incorrect oil level or internal engine faults, so diagnosis is recommended.
- Should connected components be inspected? Yes. Check the breather connections, seals and nearby hoses for cracks, oil contamination or poor sealing.
- Is this a Genuine Porsche component? This listing is for an OE Match replacement. The supplied OE reference should be used to confirm the required application.
- Which engine is this line associated with? The supplied diagram identifies it for the M48.50 engine used in the listed 955 Cayenne Turbo application.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94810721552
The product you are viewing cross references to these numbers
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
Fits:
Porsche 996 1998-02 3.4L
Porsche Boxster 986
Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610723752
The product you are viewing cross references to these numbers
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- 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
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
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.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610717550
The product you are viewing cross references to these numbers
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
AOS Oil / Air Separator
Keep your Porsche Boxster 986 running smoothly with this OE
Match Air Oil Separator (AOS). Designed for 1997-2002 Porsche
Boxster 986 models equipped with the M96 flat-six engine, the Air Oil Separator
is a vital component of the engine's crankcase ventilation system.
Fits:
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
Diagram Ref No 1
During normal operation, combustion gases and oil vapours accumulate within the engine crankcase. The Air Oil Separator separates oil particles from these gases, returning the oil to the engine while directing cleaned vapours back into the intake system for combustion. This process helps maintain engine efficiency, reduce emissions and prevent excessive oil contamination within the intake tract.
The Air Oil Separator is one of the most recognised maintenance items on Porsche M96 engines. As the internal diaphragm ages, the separator can lose its ability to regulate crankcase pressure correctly, resulting in a variety of performance and drivability issues.
Manufactured to OE Match standards, this replacement unit restores proper crankcase ventilation and helps maintain the performance and reliability expected from your Porsche Boxster.
What Does the Air Oil Separator Do?
The Air Oil Separator forms part of the Positive Crankcase Ventilation (PCV) system.
Its primary functions include:
- Separating oil from crankcase gases
- Returning oil back into the engine
- Regulating crankcase vacuum
- Reducing oil consumption
- Supporting emissions control systems
- Maintaining engine efficiency
- Preventing excessive oil contamination of the intake system
A correctly functioning AOS helps the engine breathe properly while minimising oil carryover into the intake manifold.
Why Do Air Oil Separators Fail?
The internal diaphragm and valve assembly are constantly exposed to engine heat, oil vapours and vacuum pressure.
Common causes of failure include:
Diaphragm deterioration Heat cycling Age-related wear Oil contamination Internal valve failure High mileage Crankcase pressure fluctuations Long-term exposure to engine vapoursOver time, the separator loses its ability to maintain the correct crankcase vacuum levels.
Symptoms of a Failing AOS
The Porsche Boxster Air Oil Separator often provides several warning signs before complete failure.
Common symptoms include:
- Excessive white smoke from the exhaust
- Increased oil consumption
- Rough or unstable idle
- Whistling noises from the engine
- Vacuum leaks
- Check engine warning light
- Oil contamination within the intake system
- Excessive crankcase vacuum
- Difficulty removing the oil filler cap with the engine running
These symptoms typically indicate the separator is no longer functioning correctly.
When Should the AOS Be Replaced?
Replacement should be considered when any of the above symptoms are present.
The AOS is also commonly replaced during:
- High-mileage maintenance
- Engine rebuilds
- Intake system servicing
- Preventative maintenance schedules
- Crankcase ventilation system repairs
Many Porsche specialists recommend replacing the AOS before complete failure to avoid more serious drivability concerns.
Why Replacement Matters
A failed Air Oil Separator can significantly affect engine performance and reliability.
Benefits of replacement include:
- Reduced exhaust smoke
- Improved idle quality
- Lower oil consumption
- Correct crankcase pressure regulation
- Improved engine efficiency
- Reduced intake contamination
- Enhanced reliability
- Restoration of factory engine performance
Replacing the separator early helps prevent secondary issues and maintains the health of the M96 engine.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610702304
The product you are viewing cross references to these numbers
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
AOS Oil / Air Separator
Maintain the performance and reliability of your Porsche
Boxster 986 with this OE Match Oil / Air Separator (AOS). A
critical component of the M96 engine crankcase ventilation system, the Air Oil
Separator helps separate oil vapour from crankcase gases before they are
returned to the engine intake system.
Fits:
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Diagram ref no 1
During normal engine operation, pressure builds inside the crankcase and oil vapour becomes suspended within the circulating gases. The AOS removes this oil mist, allowing the oil to return to the engine while directing cleaned gases back into the intake system for emissions control and efficient combustion.
The Air Oil Separator is a well-known service item on Porsche M96 engines. As the internal diaphragm ages and deteriorates, the separator can lose its ability to regulate crankcase vacuum correctly, leading to a variety of drivability and engine performance issues.
Manufactured to OE Match specifications, this replacement unit provides the correct fitment and performance needed to restore proper crankcase ventilation and engine operation.
What Does the Oil / Air Separator Do?
The AOS forms part of the Positive Crankcase Ventilation (PCV) system and performs several important functions.
Its primary roles include:
- Separating oil from crankcase vapours
- Returning oil to the engine
- Regulating crankcase vacuum
- Reducing oil consumption
- Supporting emissions control
- Maintaining engine efficiency
- Preventing excessive oil contamination of the intake system
Without a functioning AOS, excess oil can be drawn into the intake system and combustion chambers.
Why Do Air Oil Separators Fail?
The Air Oil Separator contains an internal diaphragm and valve assembly that is constantly exposed to heat, vacuum and engine oil vapours.
Common causes of failure include:
- Diaphragm deterioration
- Age-related wear
- Heat cycling
- Oil contamination
- Internal valve failure
- High engine mileage
- Crankcase pressure fluctuations
- Long-term exposure to engine vapours
Over time, the separator loses its ability to regulate crankcase pressure correctly.
Symptoms of a Failing AOS
A failing Air Oil Separator often produces noticeable warning signs.
Common symptoms include:
- Excessive white smoke from the exhaust
- Increased oil consumption
- Rough idle
- Vacuum leaks
- Whistling or squealing noises
- Check engine warning lights
- Oil residue in the intake system
- Excessive crankcase vacuum
- Difficulty removing the oil filler cap while the engine is running
These symptoms are common indicators that the separator requires replacement.
When Should the AOS Be Replaced?
Replacement is recommended whenever symptoms of failure appear.
The AOS should also be considered during:
- High-mileage maintenance
- Engine rebuilds Intake system servicing
- Preventative maintenance programmes
- Crankcase ventilation system repairs
Many Porsche specialists regard the Air Oil Separator as a preventative maintenance item on ageing M96 engines.
Why Replacement Matters
A failing AOS can affect engine performance, emissions and long-term reliability.
Benefits of replacement include:
- Improved idle quality
- Reduced exhaust smoke
- Lower oil consumption
- Correct crankcase pressure regulation
- Improved engine efficiency
- Reduced intake contamination
- Enhanced reliability
- Restoration of factory engine operation
Replacing a failing separator early can help prevent additional maintenance costs and drivability concerns.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610702602
The product you are viewing cross references to these numbers