Moroso Air Oil Separator  ( Part Number:MOR 85489)

Moroso Air Oil Separator

MODEL # MOR 85489
Manufacturer Part # 85489


MSRP: $406.64

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From the factory excess crankcase vapors, residual oil and moisture are vented back into the intake manifold and crankcase ventilation system. This can coat the pistons and everything else with a detonation prone layer of oil. This is no good in a turbocharged vehicle.

Moroso has come up with a 2 tank system that allows the factory crankcase ventilation to operate how it was designed. No other system on the market does this.

Billet Aluminum bodies compliment any engine compartment and can be polished, chromed or powder coated for a custom look. Each Separator has a billet aluminum clamp, a bottom drain with an elbow that makes draining the collected oil a mess-free operation. Includes stainless steel mounting brackets, 1/2" inlet and outlet fittings, 66" of 3/8" diameter and 66" of 1/2" diameter rubber hose for plumbing the Air-Oil Separators inline.

This is for cars with a TMIC and stock location turbo. This kit is not designed to be used with a FMIC or rotated mount turbo.
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Brand: Moroso
Color: Silver
Installation Hardware Included: Yes
Material: Aluminum

Mfgr. Warranty: 90 Days
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.


This product has no user uploaded media. You can upload your photo or video of your install by posting a review. Reviews:
Verified Purchase

Moroso AOS - 2013 WRX
michaelkeleman10038 3 years ago
Great product!! Solid build! Only down side is install instructions. Not as clear as one would hope...
Verified Purchase

Very nice product, but missing parts
psfp 4 years ago
The box I received came only with the hardware shown in the pictures, which means that there is some missing parts: (1) 3/8 x 90 Barbed Fitting (1) Cap used to close the cross over tube (Step 7 in user manual) Despite the missing parts, which I didn't need because I'm using a custom setup, the product works great and is nicely finished.

  • Q: Fitment with Process West Verticooler TMIC  nfreeman8597554 1 year ago


    Will these work with a Process West Verticooler TMIC in a 2013 WRX Sedan?

    • A: This is for cars with a TMIC and stock location turbo, it should work with that TMIC without any problem.

      Tyler G. 1 year ago
  • Q: Setup  Alfred 2 years ago


    Does this particular AOS system accommodate both valve covers and the pcv valve to filter out the oil vapors? Thanks.

    • A: Yes, Both valve cover breathers are Ted into one can. The crank case PCV is run through the other can before the vapors re-enter the intake.

      Moroso Performance 2 years ago
    • A: This AOS does filter oil vapor from both valve covers, the crankcase and PCV valve.

      Zach G. 2 years ago
  • Q: Difference  PROcede 5 years ago


    The difference in this unit and the other smaller body units are what exactly? Is it sized smaller for bigger intercoolers or is it sized different because one is better at filtering then the other? Is this system maintenance free like the Crawford unit?

    • A: As this uses 2 cans, there is no need to have as large of a single can that has to handle both crank case and heads. This system is not maintenance free will require draining.

      Kirill C. 5 years ago
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