AC CV-666-C Pcv Valve C5AE-6A666 Cv

( Brand: Ac ), ( Manufacturer Part Number: CV-666-C ), ( Part Type: Valve Cv ), ( Ipn: C5ae 6a666 )

Review AC Ford Original Pcv Valve Cv fits MUSTANG 1965–1966

The **1965-1966 Ford Mustang PCV Valve (Part Code: AC C5AE 6A666)** is a critical yet often overlooked component in the engine management system of these iconic muscle cars, playing a pivotal role in maintaining optimal performance, emissions compliance, and long-term engine health. Designed specifically for the early-generation Mustang s 260, 289, and 390 cubic-inch V8 engines, this Positive Crankcase Ventilation (PCV) valve is engineered to regulate the flow of blow-by gases a byproduct of combustion from the crankcase back into the intake manifold, preventing oil dilution and reducing harmful emissions. Crafted from durable materials, including a robust housing and a precision-engineered internal diaphragm or spring-loaded mechanism, the valve ensures a consistent and controlled flow of gases, which helps maintain proper crankcase pressure and prevents oil leaks or sludge buildup in the engine s lubrication system. For collectors and restorers of these classic Mustangs, sourcing an authentic OEM or high-quality aftermarket PCV valve is essential, as a failing or incorrect valve can lead to rough idling, excessive oil consumption, or even catastrophic engine damage over time. Whether installed in a meticulously restored 1965 Shelby GT350 or a daily-driven 289 V8, this valve exemplifies the blend of simplicity and ingenuity that defined Ford s engineering in the mid-1960s, ensuring that these legendary cars continue to roar with the same power and reliability they were built for.

### **Pros and Cons of Buying a 1965-1966 Ford Mustang with a PCV Valve Issue (AC C5AE 6A666 1965 1966 Ford Mustang PCV Valve CV)**

#### **Pros**

1. **Classic Mustang Appeal** The 1965-1966 Mustang is one of the most iconic American muscle cars, with a strong following among collectors and enthusiasts. Its timeless design, V8 power, and historical significance make it a desirable purchase for those who appreciate automotive history.

2. **Potential for Restoration or Modification** These Mustangs are highly customizable, whether you want to restore them to showroom condition, build a street rod, or modify them for track use. The aftermarket support for parts and upgrades is extensive, making it easier to bring one back to life or enhance its performance.

3. **Strong Community and Networking** Owning a classic Mustang connects you to a passionate community of owners, restorers, and mechanics. Local clubs, online forums, and events provide access to knowledge, parts, and camaraderie, which can be invaluable for maintenance and project support.

4. **Potential for Appreciation** Well-preserved or restored 1965-1966 Mustangs can appreciate in value, especially if they are rare or have unique features (e.g., limited editions, special paint schemes, or originality). A properly maintained example can become a sound investment over time.

5. **Driving Experience** The raw, unfiltered power of a 289 or 390 V8 in a lightweight Mustang provides an exhilarating driving experience that modern cars often lack. The simplicity of the drivetrain and the tactile feedback from the engine make it a rewarding car to drive.

6. **Affordability Compared to Later Models** While prices vary, many 1965-1966 Mustangs are more affordable than later muscle cars (e.g., 1967-1969 models), making them accessible to buyers who want a piece of Mustang history without the premium price tag of a fully restored classic.

7. **Engineering Simplicity** The early Mustangs use straightforward mechanical systems (e.g., carbureted engines, manual transmissions, and basic suspension) that are easier to understand and repair than modern fuel-injected or computer-controlled vehicles. This can be appealing to DIY mechanics.

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#### **Cons**

1. **PCV Valve and Engine Reliability Issues** The **PCV (Positive Crankcase Ventilation) valve** in these Mustangs was prone to failure, leading to oil leaks, sludge buildup, and potential engine damage if neglected. A clogged or failing PCV valve can cause excessive crankcase pressure, leading to leaks at gaskets, seals, or even a blown head gasket. The **CV (camshaft drive) valve** (often referred to as the "cam chain tensioner" or "cam drive seal") is another weak point, as leaks here can lead to oil starvation of the camshaft, causing catastrophic engine failure.

- **Fixing these issues** requires either replacing the PCV valve (relatively cheap) or addressing more serious problems like a blown head gasket, oil leaks, or cam drive seal failure (which can be costly).

- **Solution:** Ensure the seller has documented maintenance records for PCV and CV valve replacements, or budget for these repairs upfront.

- **Oil changes** (every 3,000 5,000 miles, depending on driving conditions).

- **Spark plugs** (every 10,000 20,000 miles).

- **Distributor points** (if equipped; later models switched to electronic ignition).

- **Fuel system cleaning** (carburetors clog over time).

- **Suspension and steering components** (rust, worn bushings, or failing ball joints).

- **Brakes** (drum brakes on early models are less effective than modern discs).

- **Rust** (especially in the floor pans, rocker panels, and wheel wells, common in older cars exposed to salt or moisture).

- **Ignorance or neglect** in these areas can lead to expensive repairs or a car that won t run.

3. **Parts Availability and Cost** While parts for the Mustang are widely available, some original components (especially for less common models or rare options) can be expensive or difficult to source. Replacement parts may require sourcing from specialty suppliers, eBay, or restoration shops, adding to the cost.

- **ABS or modern braking systems** (drum brakes on early models are less effective in stopping power).

- **Airbags or advanced crash protection** (seat belts are the primary safety feature).

- **Modern fuel efficiency** (a 289 V8 gets around 10 12 MPG; a 390 gets even worse).

- **Comfort for daily use** (hard seats, manual transmissions, and limited climate control options).

- These cars are best suited for weekend driving, shows, or track use rather than daily commuting.

5. **Insurance Costs** Classic car insurance can be expensive, especially if the Mustang is restored or modified. Some insurers may classify it as a "high-risk" vehicle due to its age, performance, or lack of modern safety features. Shop around for specialized classic car insurance to get the best rates.

6. **Storage and Security Risks** Classic cars are prime targets for theft or vandalism. Proper storage (garage, climate-controlled facility) and security measures (alarm, GPS tracking, immovable title) are essential to protect your investment.

7. **Time-Consuming Projects** Restoring or even maintaining a 1965-1966 Mustang is a **long-term commitment**. If you re not prepared for the time, effort, and occasional frustration of working on a project car, it may not be the right purchase.

- **Rust** (especially in the frame, floor pans, or suspension).

- **Worn-out suspension components** (shocks, springs, bushings).

- **Electrical issues** (failing alternators, starters, or wiring).

- **Transmission problems** (slipping gears, fluid leaks).

- **Exhaust or intake leaks** (common in older engines).

- A **pre-purchase inspection (PPI) by a trusted mechanic** is highly recommended before buying.

9. **Resale Value Depends on Condition** Unlike modern cars, the resale value of a classic Mustang is heavily tied to its **condition, originality, and documentation**. A well-documented, restored example will hold value, while a neglected or poorly maintained one may depreciate quickly.

10. **Legal and Registration Hurdles** Some states have **smog or emissions requirements** for classic cars, which may require additional testing or modifications. Additionally, **title restoration** (if the car is salvaged or has an "owner s discretion" title) can be time-consuming and costly.

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### **Conclusion**

Buying a **1965-1966 Ford Mustang** is a rewarding but challenging endeavor. It s a car that offers **unmatched classic appeal, driving excitement, and community support**, but it also demands **significant time, money, and effort** to keep it running reliably. The **PCV and CV valve issues** are critical concerns if not properly addressed, they can lead to **expensive engine damage**. However, with the right approach, this car can be a **lifelong passion project** or a **sound investment** if restored to showroom condition.

For the **right buyer** someone who enjoys working on cars, appreciates automotive history, and is prepared for the challenges this Mustang is an incredible purchase. For others, the **maintenance costs, time commitment, and potential reliability issues** may outweigh the benefits.

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### **Recommendation**

- **Choose a car with a clean title and documented maintenance** (especially for PCV and CV valve replacements).

- **Budget for a full inspection** by a trusted Mustang specialist to assess hidden issues.

- **Factor in restoration costs** (engine, transmission, bodywork, interior, etc.) this can easily exceed **$10,000 $30,000 ** depending on the car s condition.

- **Start with a simpler model** (e.g., a 2 2 or base model) if you re new to Mustangs, as they re less expensive to restore.

- **Look for a car with a recent service history** (oil changes, PCV/CV valve replacements, spark plugs, etc.).

- **Prioritize reliability over originality** a well-maintained 1965 Mustang with a rebuilt engine and transmission is more enjoyable than a "perfect" but neglected one.

- **Test drive thoroughly** listen for unusual noises, check for leaks, and ensure the car starts and drives smoothly.

3. **If you re

Details:

Been stored in doors for decades. Used AC CV 666- C PCV valve as pictured along with Ford engineering part number. Do your research to determine if this part will work for you.

part #: cv666 prices

• $11.85-$19.99

specifications emissyste:

• for models: Mustang
• for makes: Ford
• for years: 1965-1966
• brand: Ac
• mpn: Cv-666-c
• part type: Valve Cv
• ipn: C5ae 6a666

seller emissyste:

• # reviews: 2629
• rating: 100.0%
• city: Simi Valley, California

general emissyste:

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

payments emissyste:

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

offer emissyste:

• sold: 0
• quantity: 1
• best offers: True
• options: Ship-to-home
• started: February 2, 2026
• availability: In Stock

shipping emissyste:

• service: USPS Ground Advantage
• carrier: USPS
• class: Standard
• cost: $0.00
• type: Fixed
• transit: 3-8 Days

returns emissyste:

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

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