AOS Oil / Air Separator. Porsche 996 / 997.1 Carrera 3.6L 2000-08  ❭  99610702652

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.

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.
• Diagram Ref No 1.

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.

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.

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.