1. Cylinder Heads & Parts Engines Components For Sale
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  3. VOLKSWAGEN JETTA

VOLKSWAGEN 306-58123 Cylinder Head Valve Engine Rd 1.8

fits model: Jetta. make: Volkswagon, Volkswagen. year: 1985–1988.

306-58123 Volkswagen 85-88 Volkswagon Jetta Cylinder Head 1.8 Liter 8 Valve Engine Id Rd

( Brand: Volkswagen ), ( Part Type: Valve Cylinder Head Engine ), ( Conditions Options: Cfa ), ( Genuine Oem: Yes ), ( Ipn: 306-58123 ), ( Descriptionpartcondition: 1.8 Liter )

Review VOLKSWAGEN Volkswagon Cylinder Head 1.8 Liter Valve Engine Id Rd fits JETTA 1985–1988

The **Volkswagen 306-58123 cylinder head** is a precision-engineered component designed exclusively for the **1.8L RD (R4) inline-four engine** found in the **1985 1988 Volkswagen Jetta**, as well as select models from the **Rabbit (MK2)** and **Golf (MK2)** platforms. This cast aluminum head is a critical part of the engine s combustion system, housing the **four intake and exhaust valves per cylinder**, the **spark plug bores**, and the **camshaft mounting surfaces**, all of which work in tandem to ensure optimal performance, efficiency, and reliability. The **1.8L RD engine** often referred to as the "1.8L 8V" or "1.8L 8V RD" due to its single overhead camshaft (SOHC) design with eight total valves relies on this cylinder head to maintain proper valve timing, compression, and cooling, making it a high-demand replacement part for restorers, mechanics, and enthusiasts seeking to restore or upgrade their classic Volkswagen.

This cylinder head is manufactured to strict Volkswagen specifications, featuring **precision-machined valve seats, guide bores, and a smooth combustion chamber surface** to minimize carbon buildup and maximize combustion efficiency. The **intake and exhaust ports** are carefully contoured to optimize airflow, contributing to the engine s characteristic smooth yet spirited performance, particularly when paired with a properly tuned carburetor or fuel injection system. The **spark plug bores** are designed to accommodate standard **NGK or Bosch plugs**, ensuring reliable ignition and consistent power delivery. Additionally, the head includes **integrated water passages** for effective cooling, preventing overheating and thermal stress that could lead to warping or failure over time.

For those working on a **1985 1988 Volkswagen Jetta**, this cylinder head is a **direct-fit replacement**, eliminating the need for modifications or adapters. It is compatible with both **carbureted (e.g., Solex or Hitachi) and early fuel-injected (e.g., KE-Jetronic) versions** of the 1.8L RD engine, making it a versatile choice for restoration projects. When installing, it is essential to use a **high-quality gasket (such as a Volkswagen OEM or aftermarket equivalent) and proper torque specifications** to prevent leaks and ensure a secure seal. The head also requires **valve adjustment** every **30,000 40,000 miles** to maintain proper valve lash, which is a straightforward process for those familiar with basic engine maintenance.

Beyond its functional role, this cylinder head holds **historical significance** as part of Volkswagen s transition from carbureted to early electronic fuel injection systems in the mid-1980s. The **1.8L RD engine** was a popular choice for its balance of power, fuel efficiency, and reliability, making it a staple in European compact cars of the era. Whether you're restoring a **1986 Jetta GL with a Solex carburetor** or upgrading a **fuel-injected Rabbit**, this cylinder head is a **critical component** that ensures the engine runs as intended smooth, responsive, and free from the common issues like **leaking head gaskets, warping, or valve train wear** that can plague older Volkswagen engines.

For mechanics and DIY enthusiasts, sourcing an **authentic Volkswagen 306-58123 cylinder head** ensures compatibility with the original engine bay layout, including proper **bolt patterns, mounting points, and alignment** with the intake manifold and exhaust headers. While aftermarket alternatives exist, a **genuine Volkswagen part** guarantees the correct material properties, machining tolerances, and durability expected from the manufacturer. Whether you're tackling a **full engine rebuild** or simply replacing a failed head due to overheating or corrosion, this component is a **cornerstone of restoring your 1.8L RD-powered Volkswagen** to its original performance specifications. With proper care and maintenance, it will serve as a reliable foundation for years of trouble-free driving.

### Pros and Cons of Buying a Volkswagen 306-58123 Cylinder Head (1.8L Valve Engine, RD, 1985 1988 Volkswagen Jetta)

#### **Pros:**

1. **Common and Widely Available** The 1.8L valve engine (RD) in the 1985 1988 Jetta is a well-documented and frequently encountered engine. Parts, manuals, and repair guides are abundant, making it easier to diagnose and fix issues.

2. **Mechanically Simple** Compared to modern engines, this inline-four has a straightforward design with fewer electronic components. This means repairs can often be done with basic tools and without specialized diagnostic equipment.

3. **Affordable Replacement Cost** Since this engine is older, a used or rebuilt cylinder head is relatively inexpensive compared to newer Volkswagen or modern engine components. You can often find one for under $200 $400, depending on condition.

4. **Aftermarket Support** There is a strong aftermarket presence for this engine, including remanufactured heads, gaskets, and performance upgrades. Companies like **Eagle, JE, and Performance Auto** offer rebuilt heads and kits.

5. **Good for Learning** If you're mechanically inclined, working on this engine provides hands-on experience with traditional engine mechanics, including valve adjustment, head gasket replacement, and basic machining.

6. **Potential for Performance Mods** With the right modifications (e.g., porting, upgraded valves, or a performance cam), this engine can be tuned for better power, though stock reliability is already decent for its class.

7. **No Major Electronic Issues** Unlike later VW engines with complex fuel injection or emissions systems, the RD engine relies on a carburetor (in early models) or a simple throttle-body injection (TBI), reducing the risk of electronic failures.

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#### **Cons:**

1. **Potential for Wear and Tear** The 1.8L valve engine is known for **head gasket failures**, **warped cylinder heads**, and **camshaft wear** over time. If the head you're buying has been neglected, these issues could recur.

2. **Valvetrain Wear** The pushrods, rocker arms, and lifters in this engine can wear out, leading to **valve float or excessive lash**, which affects performance and longevity. A thorough inspection is crucial.

3. **Limited Lifespan Without Maintenance** If the engine was never properly maintained (oil changes, valve adjustments, head gasket replacements), it may have **internal damage** (scored cylinders, worn bearings) that isn t immediately obvious.

4. **Rebuilt vs. Used Head Quality** A "used" head might be salvaged from a wrecked engine with hidden damage. A **rebuilt head** is safer but still depends on the quality of the rebuild. Always ask for proof of machining and inspection.

5. **Emissions and Modern Compliance** If you plan to keep the car for long-term use, modern emissions regulations may require modifications (e.g., upgrading to a modern catalytic converter or fuel system), adding unexpected costs.

6. **Rust and Corrosion Risks** Older VWs, especially in wet climates, are prone to **frame and suspension rust**, which can affect the head s mounting surface if not addressed.

7. **Limited Warranty Options** Since this is a used or rebuilt part, warranties (if any) are typically short-term (30 90 days). Major failures after purchase may not be covered.

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### **Key Considerations Before Purchase:**

- **Inspect for Warping** Use a straightedge and feeler gauges to check for head warpage. A warped head can cause poor sealing and overheating.

- **Check Valve Condition** Look for pitting, burns, or excessive wear on the valve seats and faces. Regrinding may be needed.

- **Test the Head for Leaks** If possible, pressure-test the head to ensure it doesn t leak around the valves or gasket surface.

- **Verify Rebuild Quality (if applicable)** Ask for documentation showing the head was properly machined, gasket surfaces were refinished, and components were replaced if worn.

- **Consider the Engine s Full Condition** A head alone won t fix a failing engine. Ensure the block, crankshaft, and other components are in decent shape.

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### **Conclusion and Recommendation:**

Buying a **1985 1988 Volkswagen Jetta 1.8L valve engine (RD) cylinder head (part #306-58123)** can be a **cost-effective solution** if you need a replacement for a known issue (e.g., blown head gasket, warped head). The engine s simplicity and widespread availability make it a practical choice for DIYers or those working on classic VWs.

**However, the risks of hidden damage, wear, and potential future failures mean you should:**

1. **Prioritize a rebuilt head from a reputable shop** over a used one.

2. **Inspect thoroughly** for warping, valve condition, and signs of past neglect.

3. **Budget for additional repairs** the head alone may not be enough if the engine has broader issues.

4. **Consider a remanufactured engine** if you want a more comprehensive fix (though this is more expensive).

**Final Recommendation:**

If you re confident in your mechanical skills and can verify the head s condition, purchasing a **rebuilt 306-58123 cylinder head** is a reasonable investment. For a more foolproof solution, a **full engine rebuild or remanufactured engine** may be worth the extra cost. Always weigh the immediate need against the long-term reliability of the part.

Details:

Good Used Part This is a good tested used part. Vehicle has collision damage but the items was untouched in accident. If you are looking for a good, used guaranteed item this is the one. JETTA GLI 85-86 1.8L.

This is a nice used part ready to be installed in your vehicle.

specifications cylinderheapar:

  • for models: Jetta
  • for makes: Volkswagon, Volkswagen
  • for years: 1985-1988
  • brand: Volkswagen
  • part type: Valve Cylinder Head Engine
  • conditions options: Cfa
  • genuine oem: Yes
  • ipn: 306-58123
  • descriptionpartcondition: 1.8 Liter

seller cylinderheapar:

  • city: Lynn, Massachusetts
  • # reviews: 7016
  • rating: 98.8%

shipping cylinderheapar:

  • transit: 4-7 Days
  • class: Standard
  • cost: $0.00
  • carrier: UPS
  • type: Fixed
  • service: UPS Ground

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general cylinderheapar:

  • condition: Used
  • Car Truck Parts Accessories > Engines Engine Parts > Other Engine Parts

offer cylinderheapar:

  • started: February 20, 2026
  • best offers: True
  • availability: In Stock
  • options: Ship-to-home
  • quantity: 1
  • sold: 0

returns cylinderheapar:

  • time: 30 Days
  • policy: Returns Accepted
  • paid by: Buyer
for models: jetta, for makes: volkswagon, volkswagen, for years: 1985-1988, part type: valve cylinder head engine, conditions options: cfa, genuine oem: yes, descriptionpartcondition: 1.8 liter,
manufacturer: volkswagen, category: auto parts > car truck parts accessories > engines engine parts > engine parts, sku: 11568597006596751,
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