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Subaru Wrx Engine Oil Separator Covers

Subaru Wrx Engine oil separator covers

Starting at low prices, AutoBuffy stocks multiple engine oil separator covers from top OE-quality brands for the Subaru Wrx. The oil separator cover seals the positive crankcase ventilation (PCV) chamber, keeping oil mist from entering the intake system. When it cracks or warps, oil is pulled into the intake, causing rough idle, increased emissions, and accelerated engine wear.

Signs your Subaru Wrx needs a new engine oil separator cover

  • Rough or unstable idle that worsens when the engine is warm — oil vapor disrupting the air-fuel mixture
  • Visible oil residue or buildup inside the intake manifold or throttle body bore
  • Oily, acrid smell from the engine bay or cabin vents, caused by burning oil pulled through the PCV system
  • Increased oil consumption with no obvious external leak — oil is being burned off through the intake
  • Check Engine light with codes related to lean fuel trim (e.g., P0171, P0174) caused by an unmetered air leak at a cracked cover
  • White or blue-gray smoke from the exhaust, particularly at idle or deceleration, indicating oil burning in the combustion chamber

Which engine oil separator cover should you buy for your Subaru Wrx?

The primary decision is whether to replace with an OEM-equivalent part or upgrade to a reinforced aftermarket unit. Factory covers on many engines are made from plastic that becomes brittle with heat cycling over time, so some owners choose covers made from more durable materials. Fit and sealing surface quality matter most — a poorly fitting cover will leak regardless of material.

OEM Replacement (plastic)
Best for
Restoring factory spec at lowest cost
What you get
Exact fit, correct PCV flow geometry, direct bolt-on with no modification
OEM-Equivalent Aftermarket
Best for
Budget-conscious repairs with reliable fit
What you get
Comparable materials and dimensions to factory, often priced below dealer cost
Reinforced / High-Temp Aftermarket
Best for
High-mileage engines or vehicles in hot climates
What you get
Thicker walls or heat-resistant compounds that resist warping and cracking longer than stock plastic
Cover + Gasket Kit
Best for
Complete repair in one purchase
What you get
Matched cover and sealing gasket to eliminate oil seepage at the mating surface, recommended when reusing the old gasket is risky

Replacing the engine oil separator cover on a Subaru Wrx

Moderate⏱ 1–2 hoursSocket set and ratchet (metric or standard depending on vehicle)Torque wrench for cover boltsPlastic trim removal tools or flathead screwdriver (to avoid damaging surrounding components)Gasket scraper or plastic razor blade (to clean the mating surface)Clean lint-free rags and brake cleaner or engine degreaser

Access to the oil separator cover varies considerably by engine layout — on some Subaru Wrx applications it is visible near the top of the valve cover, while on others it is tucked behind intake components requiring partial disassembly. Always clean the mating surface thoroughly before installing the new cover and gasket to ensure a proper seal. Tighten the cover bolts evenly in a cross pattern to avoid warping the new cover, following the manufacturer's recommended snug-but-not-overtightened approach for plastic or composite housings.

Frequently asked questions

How much does it cost to replace engine oil separator covers on a Subaru Wrx?
Parts start at low prices on AutoBuffy. The cover itself is inexpensive, but labor cost depends on accessibility on your specific engine — some are straightforward 30-minute jobs while others require partial intake disassembly. DIY replacement keeps the total cost near the part price alone.
Can I drive my Subaru Wrx with a cracked or failed engine oil separator cover?
You can drive short distances, but it is not advisable. A failed cover allows oil to contaminate the intake and combustion chamber continuously. Over time this fouls oxygen sensors, catalytic converters, and spark plugs, turning an inexpensive cover replacement into a much costlier repair if ignored.
What causes the engine oil separator cover to fail on a Subaru Wrx?
Heat cycling is the primary cause — repeated expansion and contraction makes plastic covers brittle and prone to cracking. Sludge buildup from infrequent oil changes can also clog the separator baffle, increasing internal pressure and stressing the cover. Most failures occur on higher-mileage engines or those with a history of extended oil change intervals.
Do I need to replace the gasket when I replace the oil separator cover on my Subaru Wrx?
Yes, in almost every case. The old gasket compresses and takes a set against the mating surface. Reusing it with a new cover almost always results in oil seepage shortly after the repair. Purchasing a cover and gasket together as a kit is the most reliable approach and saves a second disassembly.
Will a failed engine oil separator cover cause a Check Engine light on a Subaru Wrx?
Yes, it commonly does. A cracked cover introduces an unmetered air leak into the PCV system, which the mass airflow and oxygen sensors detect as an unexpectedly lean fuel mixture. This typically triggers fuel trim codes such as P0171 or P0174. Replacing the cover and clearing the codes usually resolves them if no other issues are present.
How do I know if the oil separator cover or the PCV valve itself is the problem on my Subaru Wrx?
Inspect the cover first for visible cracks, warping, or oil weeping around its sealing surface. A failed PCV valve typically rattles when shaken (if it is a rattle-type) or collapses the oil filler cap onto the valve cover under suction. Both parts are inexpensive and often replaced together since they share the same service access.

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