Andair Oil / Air Separator

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Part# 08-01034
MFR Model# OS850


Note: Image shows two products (08-01034 and 08-01035). They are sold separately. See Accessories tab to order 08-01035.

Manufactured from aircraft grade materials and anodised for corrosion protection, this unit is extremely light weight and rugged. The OS8850 has been designed to remove the oil from the crankcase breather on Lycoming and Continental Engines. This gives reduced oil consumption, cleaner aircraft, and environment.

The CS850 has some unique features that make it the best on the market.
  • Upper outlet can rotate through 360 allowing easy installation.
  • The unit can be dismantled for inspection/cleaning.
  • Vortex swirl separation. O-Ring seals.
  • Light weight: 6.4 oz.
  • 4 off 10-32 mounting lugs on the base of the separator for easy fire wall mounting.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -



Using the Andair Oil/Air Separator since 2015 on my C-A185F in conjunction with the CT850 trap. After several hours of flying the trap has about a teaspoon or less oil and depending on the flying environment a few drops of emulsified water/oil captured. No delectable oil on the belly from the case vent. Since the condensed oil and occasionally some emulsified water/oil is captured in the CT850 trap and NOT RETURNED to the engine it keeps that oil from contributing to engine corrosion. A very well machined and designed product and beautifully finished.

William O
November 17, 2022

Just installed this on a Sportsman with a Lyc IO-390. Added 8 qts of oil with oil change and it's still at 8 qts after several hours of flying. Adding 8 qts before installing the air/oil sep would immediately blow out any oil above 6-1/2 qts.

Kurt E
July 25, 2014


Please note,'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: What are the dimensions of the Andair Oil / Air Separator including inlet / outlet sizes?

We have added the dimensions PDF to the "Dimensions" tab of the web page. Please review them there.

Q: Is this FAA approved? They advertise that it is standard equipment on SR-22s? It must be approved in some manner. Thanks Kurt Malerich

The unit itself does not have an FAA approval. Cirrus may have included it for their OEM STC, but I could not find any info that Cirrus uses this as standard equipment.