SUBARU 42084SA020 Vent Valve

( Manufacturer Part Number: 42084SA020 ), ( Part Type: Valve Vent ), ( Genuine Oem: Yes ), ( Manufacturer Warranty: 1 Year ), ( Universal Fitment: Direct Replacement ), ( Year: 2005 2006 2007 2008 ), ( Parts Included: Only Part Reference 19 On The Diagram Is Included )

Review SUBARU Genuine Vent Valve fits 2005–2008

The **Subaru 42084SA020 Vent Valve** is a precision-engineered component designed specifically for Subaru engines, serving as a critical element in the vehicle s fuel injection and emissions control systems. This vent valve, often referred to as a purge control valve or canister purge valve, plays a vital role in maintaining optimal fuel vapor management within the vehicle s evaporative emission control system (EVAP). Located between the fuel tank and the engine s intake manifold, it regulates the flow of fuel vapors stored in the charcoal canister, ensuring they are properly drawn into the combustion chamber during idle or low-load conditions. Crafted from high-quality materials, this valve is built to withstand the demanding operating environment of a Subaru engine, featuring a durable housing and a reliable internal mechanism that includes a solenoid actuator and a precision-machined valve seat. The design incorporates a sealed diaphragm or membrane that opens and closes in response to vacuum signals from the engine s intake manifold, allowing for precise control over the venting process. This not only enhances engine performance by delivering a consistent air-fuel mixture but also helps reduce harmful emissions by preventing fuel vapors from escaping into the atmosphere. Whether installed in a Subaru WRX, Outback, Legacy, or Forester, this vent valve is engineered to meet strict OEM specifications, ensuring compatibility and reliability. Its robust construction and seamless integration with the vehicle s electronic control module (ECM) make it an essential part of maintaining both efficiency and compliance with emissions regulations. For Subaru owners seeking a direct replacement for a faulty or worn-out vent valve, this part offers a dependable solution that restores proper EVAP system function, prevents check engine light activation, and supports overall engine health.

The **Subaru 42084SA020** is a **vent valve** used in the **Subaru EJ25 engine s turbocharger system**, specifically for the **EJ257 (2005 2011) and EJ258 (2011 2014) models**. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

---

### **Pros of buying a Subaru 42084SA020 Vent Valve**

1. **Direct OEM Replacement** This is a genuine Subaru part, ensuring compatibility with the EJ25 turbocharger system. It matches the original specifications in terms of material, size, and function, reducing the risk of fitment issues.

2. **Reliability and Durability** Subaru s OEM components are designed to withstand the high pressures and temperatures found in turbocharged engines. The vent valve helps regulate boost pressure by allowing excess air to escape, preventing over-boost conditions that could damage the turbo or engine.

3. **Prevents Turbo Damage** A failing vent valve can lead to **over-boosting**, which stresses the turbocharger s bearings and can cause catastrophic failure. A new vent valve ensures proper boost control and extends the turbo s lifespan.

4. **Easy Installation** The vent valve is a relatively simple component to replace, requiring only basic tools. It is typically located near the turbocharger s wastegate or on the intercooler piping. Many mechanics and DIYers can install it without specialized equipment.

5. **Cost-Effective for Long-Term Use** While the part itself is not extremely expensive (typically **$20 $50** depending on the source), replacing it early prevents far costlier repairs, such as a **blown turbocharger or engine damage** from over-boosting.

6. **Improves Engine Performance** A properly functioning vent valve ensures the turbocharger spools up efficiently, leading to **better throttle response, power delivery, and fuel efficiency** compared to a failing or clogged valve.

7. **Warranty Coverage (If Purchased New)** If buying from an authorized Subaru dealer or a reputable aftermarket supplier, the part may come with a warranty, providing peace of mind against early failure.

8. **Compatibility with Modifications** Even if you ve modified your EJ25 (e.g., with a larger turbo or upgraded intercooler), the vent valve remains a critical component for maintaining proper boost control. A high-quality replacement ensures it keeps up with increased airflow demands.

---

### **Cons of buying a Subaru 42084SA020 Vent Valve**

1. **Potential Counterfeit Parts** The aftermarket for Subaru parts is flooded with **fake or low-quality replicas**, especially on eBay, Amazon, or untrusted suppliers. These can fail prematurely, leading to the same issues they were supposed to fix. Always verify the seller s reputation and part authenticity.

2. **Limited Lifespan in Harsh Conditions** While the vent valve itself is durable, **carbon buildup from oil or fuel** can clog it over time, especially in engines with **poor maintenance (oil changes, air filters, or fuel system issues)**. Regular cleaning or replacement of the entire turbocharger system may be necessary.

3. **Requires Professional Inspection** If the vent valve is failing, it may be accompanied by **other turbocharger issues** (e.g., worn bearings, cracked housing, or failing wastegate). Simply replacing the vent valve without addressing these can lead to recurring problems. A **full turbo inspection** is recommended before replacement.

4. **Installation Risks if Not Done Correctly** While straightforward, improper installation (e.g., incorrect torque, misalignment, or sealing issues) can cause **leaks or reduced performance**. Using the wrong gaskets or failing to clean the mounting surfaces can lead to boost leaks or turbo damage.

5. **Cost of Associated Repairs** If the vent valve failure is due to **underlying turbocharger wear**, replacing just the vent valve may not be enough. You might need to budget for a **full turbo rebuild or replacement**, which can cost **$1,000 $2,500 ** depending on the turbo s condition.

6. **Environmental Factors** Engines in **dusty, humid, or salt-laden environments** (e.g., coastal areas) may experience **premature wear** on turbo components, including the vent valve. Regular maintenance (e.g., oil changes with **high-quality synthetic oil**) can mitigate this.

7. **Aftermarket Alternatives May Be Better** Some aftermarket manufacturers (e.g., **TurboTech, Garrett, or Apexi**) offer **enhanced vent valves** designed for **higher boost or modified engines**. These may provide **better durability or performance** than the stock OEM part, though they may not be a direct drop-in replacement.

8. **Potential for Misdiagnosis** Symptoms of a failing vent valve (e.g., **boost leaks, rough idle, or turbo lag**) can also indicate **other issues** (e.g., a bad wastegate, cracked turbo housing, or vacuum leaks). Without proper diagnostics, you might waste money replacing the vent valve when another component is at fault.

---

### **Conclusion**

The **Subaru 42084SA020 vent valve** is a **critical and cost-effective OEM replacement** for maintaining proper turbocharger function in the EJ25 engine. Its primary role in **preventing over-boosting and protecting the turbocharger** makes it a **necessary part for long-term reliability**. However, its effectiveness depends on **proper installation, sourcing genuine parts, and addressing any underlying turbocharger issues**.

If your engine is **running normally otherwise** and the vent valve is the only suspected failing component, replacing it is a **wise preventive measure**. However, if the turbocharger is **old or has been neglected**, a **full inspection and potential rebuild** may be more economical in the long run.

---

### **Recommendation**

1. **Source the Part from a Trusted Supplier**

- **Best option:** Purchase from an **authorized Subaru dealer** or a **reputable aftermarket supplier** (e.g., **RockAuto, TurboTech, or a local Subaru specialist**).

- **Avoid:** Cheap eBay or Amazon listings without seller reviews or return policies, as they may be counterfeit.

2. **Inspect the Turbocharger System First**

- **Turbo bearing wear** (listen for whining noises).

- **Wastegate or actuator issues** (can cause similar symptoms).

- **Carbon buildup or oil leaks** (common in older EJ25 engines).

- If the turbo is **beyond 100,000 miles or shows signs of wear**, consider a **full rebuild or replacement** rather than just the vent valve.

3. **Follow Proper Installation Procedures**

- Clean the **mounting surfaces** thoroughly.

- Use the **correct gaskets or seals** (Subaru may provide them with the part).

- Ensure **proper torque specifications** to avoid leaks.

- Check for **boost leaks** after installation (use a **boost gauge** to verify proper operation).

4. **Consider an Upgraded Vent Valve for Modified Engines**

- If you ve **added a larger turbo or upgraded intercooling**, a **high-flow aftermarket vent valve** (e.g., from **TurboTech or Apexi**) may improve performance and longevity.

5. **Maintain the Turbocharger System**

- Use **high-quality synthetic oil** (e.g., **Motul, Pennzoil Platinum, or Mobil 1**) and change it **every 5,000 7,500 miles**.

- Replace the **oil filter and air filter** regularly to prevent carbon buildup.

- Consider **turbo cleaner additives** (e.g., **Berg Freeze or CRC Turbo Cleaner**) to reduce carbon deposits.

6. **Monitor Performance After Replacement**

- Listen for **unusual noises** (whining, rattling, or hissing).

- Check for **boost leaks** (a **boost gauge** is invaluable).

- If symptoms persist, **re-inspect the turbocharger** for other failures.

---

### **Final Verdict**

- You ve confirmed it s the **only failing component**.

- You re sourcing it from a **trusted supplier**.

- Your engine is **otherwise healthy** (no turbo wear, leaks, or vacuum issues).

- The turbocharger is **old or neglected** (a full rebuild may be needed).

- You suspect **other issues** (wastegate, housing cracks, etc.).

- You re buying from an **unverified seller** (risk of counterfeit parts).

- **Replace the vent valve as a preventive measure** if the engine is under **50,000 70,000 miles**.

- **Inspect and service the turbocharger system** every **50,000 75,000 miles** to catch issues early

Details:

Subaru of the Rockies. Parts must be resalable and in the original packaging. Shipping Carrier substitutions may be made at our determination in an attempt to reduce shipping cost the customer. Electrical parts are not returnable.

part #: 42084sa020 prices

• $95.81-$136.73

specifications emissyste:

• for makes: Subaru
• for years: 2005-2008
• mpn: 42084sa020
• part type: Valve Vent
• genuine oem: Yes
• manufacturer warranty: 1 Year
• universal fitment: Direct Replacement
• year: 2005 2006 2007 2008
• parts included: Only Part Reference 19 On The Diagram Is Included

returns emissyste:

• policy: Returns Accepted
• time: 30 Days
• paid by: Seller

offer emissyste:

• started: May 26, 2026
• sold: 0
• options: Ship-to-home
• quantity: 1
• availability: In Stock

shipping emissyste:

• type: Fixed
• cost: $9.00
• class: Standard, Expedited, One-day
• transit: 3-7 Days
• service: Standard, Expedited, Overnight

payments emissyste:

• other
• wallet: Apple-pay
• credit card: Discover

general emissyste:

• condition: New
• Car Truck Parts Accessories > Exhaust Emission Systems > Other Exhaust Emission Parts

seller emissyste:

• rating: 99.9%
• # reviews: 6067
• city: Boulder, Colorado

Subaru 42084SA020 Is Similar To:

• 0951bg110 Subaru Genuine Hose Fuel (51.4% similar) In stock orders ship within 24 hours. At sybarites. Electrical parts are not returnable. And sybarites. Shipping carrier substitutions may be made at our determination in an attempt to reduce cost the customer. Does not show real time inventory. Parts must be resalable and in the original packaging...(March 8th, 2018)
• 11810aa021 Subaru Oem Pcv Valve (44.8% similar) Subaru oem PVC valve 11810AA022 legacy outback 6 cylinder...(December 9th, 2017)
• 11810aa040 Subaru New Oem Pcv Valve (45.1% similar) Brand new PVC valve 11810AA040 fits many different Subaru's. Check part number before buying it to make sure will fit your car...(March 15th, 2018)
• 11810aa100 Subaru Oem Pcv Valve Impreza Forester Outback Legacy Tribeca Xv (27.3% similar) Oem subaru PVC valve impress forester outback legacy tribe ca xv...(April 4th, 2018)
• 11810aa120 Subaru Pcv Valve Impreza Wrx Forester Xt Turbo Oem (26.8% similar) Its green call dealer for fit...(May 22nd, 2018)
• 11815ab711 Subaru Genuine Pcv Valve Hose Kit Wrx Sti Turbo Oem (42.9% similar) Shipped with USPS first class package. Genuine subaru PVC valve hose kit Rx sit turbo EJ205 EJ255 EJ257 oem new. Condition is used...(March 4th, 2019)
• 11849aa140 Subaru Legacy Outback Pipe Assembly Pcv Valve (41.3% similar) Please for costs to other areas. Number on part: 11849AA140...(July 31st, 2018)
• 147 49002 602 Wd Express Vapor Canister Vent Fits Subaru Forester (19.8% similar) Bean wagon 4-DOOR, limited 30TH anniversary sedan outback postal rs coupe 2-DOOR,S sport crew cab pickup sports ET, Mon to Fri. Bean edition wagon 4-DOOR, XS XLS XLT limited premium 4-DOOR...(December 25th, 2018)
• 14710aa780 Subaru Genuine Oem Egr Valve (58.7% similar) ...(October 5th, 2018)
• 14774aa271 Subaru Genuine Solenoid Valve (60.5% similar) All cores must be shipped to: sybarites. At sybarites. You can trust sybarites. Parts must be resalable and in the original packaging. Orders are shipped when they complete only. Our subaru parts team is here to help. Shipping carrier substitutions may be made at our determination in an attempt to ...(March 8th, 2018)
• 14774aa371 Subaru Genuine Svx Solenoid Valve (57.5% similar) Electrical parts are not returnable. In stock orders ship within 24 hours. All cores must be shipped to: sybarites. And sybarites. Parts must be resalable and in the original packaging. Shipping carrier substitutions may be made at our determination in an attempt to reduce cost the customer. At ...(March 8th, 2018)