do not press the back button…
Enter your VAT number here and click Verify:
Your details have been verified. VAT number registered to:
,
.
Your order will now be zero rated for VAT purposes. We reserve the right to verify these details after your order request has been made and reinstate VAT if required.
Your VAT details were not recognised or were invalid. Your VAT number must be matched to your Billing Country as specified above. This is currently specified as . You do not need to enter the country code part of your VAT number as this has already been selected in your billing address details above.
The VAT number checking service is currently offline. Please supply your VAT details within the comments or special instructions field below and we will apply a VAT discount after placing your order request.
- 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 996 TURBO 2000-05
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
This AOS oil / air separator by OE Match is listed for Porsche 996 and 997.1 3.6L applications, including the Carrera variants detailed in the fitment section.
Fits
- Porsche 996 (911) 1997–2005
- Porsche 996 Carrera 2 3.6L 09/2001–2005
- Porsche 996 Carrera 4 3.6L 09/2001–2005
- Porsche 996 Carrera 4S 3.6L 09/2001–2005
- Porsche 996 Turbo 2000–05
- Porsche 997 (911) Mk1 2005–08
- Porsche 997 Mk1 Carrera 2 3.6L 2005–08
- Porsche 997 Mk1 Carrera 4 3.6L 2005–08
Check fitment for your specific vehicle (model, year, engine) before ordering.
Diagram Ref No 1.
What This Product Does
The air/oil separator forms part of the engine crankcase ventilation system. It removes suspended oil droplets from blow-by gases before the gases are directed towards the intake. Separated oil can return to the crankcase, helping to limit the amount of liquid oil reaching the intake tract.
Functions
- Separates oil mist from crankcase gases.
- Supports controlled crankcase ventilation.
- Returns separated oil towards the engine crankcase.
- Routes treated blow-by gases into the intake system.
- Helps prevent excessive oil contamination within the intake.
Technical Details
- Part number: 99610702652.
- Related earlier reference: 99610702651.
- Component type: air/oil separator for the crankcase ventilation system.
- Diagram application: Porsche 996 Carrera 2, Carrera 4 and Carrera 4S with M96.03 engine from 2002.
- Diagram application: Porsche 997.1 3.6L Coupé and Cabriolet with M96.05 engine, 2005–08.
Symptoms of Fault
- Heavy white or blue exhaust smoke, particularly after starting or idling.
- Increased engine oil consumption.
- Rough, unstable or hunting idle.
- Whistling or honking sounds from the crankcase ventilation system.
- An oil filler cap that is unusually difficult to remove because of excessive vacuum.
- Oil deposits around the throttle body or intake pipework.
- Misfire or mixture-related faults where oil or unmetered air enters the intake.
- Cracked, brittle or leaking associated breather lines.
Why Replacement Matters
A deteriorated separator may allow liquid oil to pass into the intake or create abnormal crankcase vacuum. Replacing the faulty component helps restore the intended ventilation path and may address smoke, oil consumption or idle problems caused by the AOS. The adjoining vent lines, seals and connections should also be inspected because age-hardened pipes can crack when disturbed. Occasional brief smoke from a flat-six engine does not by itself confirm separator failure, so oil level, breather integrity and other possible causes should be checked before replacement.
FAQs
- Does exhaust smoke always indicate AOS failure?
No. Oil overfilling and other engine faults can produce similar symptoms, so diagnosis is recommended. - Can a faulty separator cause misfires?
Yes. Oil entering the intake or a vacuum leak within the breather system may affect combustion and foul spark plugs. - What else should be inspected?
Check the oil level and examine the vent lines, connections, seals and intake pipework for oil residue, cracks or leaks. - Is this the same separator used on a Boxster?
AOS problems are also discussed in relation to Boxster models, but this part is listed for the Porsche 996 and 997.1 applications shown above.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610702652
The product you are viewing cross references to these numbers
- Porsche 957 Cayenne S / GTS 4.8L 2007-10
Fits:
Porsche 957 Cayenne S / GTS >>2008
Click 'Zoom in' for large parts diagram.
Diagram ref no 13 (Cyl. 1-4) or 14 (Cyl 5-8).
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94810723
The product you are viewing cross references to these numbers
- Porsche 957 Cayenne S / GTS 4.8L 2007-10
Vent Line – Oil Separator to Crankcase
Fits:- Porsche 957 Cayenne S / GTS 4.8L 2007-10
Diagram ref no 1
This vent line forms part of the engine's crankcase
ventilation system, connecting the oil separator with the crankcase ventilation
circuit. It helps route blow-by gases and oil vapour correctly through the
breather system while supporting controlled crankcase pressure.
What Does the Vent Line Do?
During normal engine operation, combustion gases can pass
the piston rings and enter the crankcase. The crankcase ventilation system
manages these gases and routes oil-laden vapours through the air/oil separator
system.
This vent line provides part of that connection, allowing
vapours to move through the system while helping maintain the correct crankcase
pressure.
Why Does It Fail?
Breather and vent lines operate in a hot engine environment and are continually exposed to oil vapour.
Over time they can:
- Harden or become brittle
- Crack or split
- Develop leaks at their connections
- Become contaminated with oil residue
- Suffer damage during engine maintenance
Age-related deterioration is particularly relevant on older Cayenne models.
When Should It Be Replaced?
Inspect the vent line if there are signs of:
Visible cracking or splitting Oil residue around connections Vacuum or pressure leaks Hissing noises Rough or unstable idle PCV-related engine faults Deteriorated connector endsA damaged vent line can interfere with the operation of the crankcase ventilation system, so the associated air/oil separators and other breather hoses should also be inspected.
Checks Before Installation
When replacing the vent line, inspect:
- Air/oil separators
- Adjacent breather hoses
- Hose connections and seals
- Crankcase ventilation valves
- Intake connections
- Evidence of oil leakage
- Brittle or damaged plastic fittings
Replacing other deteriorated breather components at the same time can help avoid repeated dismantling.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94810724702
The product you are viewing cross references to these numbers
- Porsche 957 Cayenne S / GTS 4.8L 2007-10
Fits:
Porsche 957 Cayenne S / GTS 2009-10
Click 'Zoom in' for large parts diagram.
Diagram ref no 13 (Cyl 1-4) or 14 (Cyl 5-8)
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94810723
The product you are viewing cross references to these numbers