Many truck owners ask, “Does a 5.9 valve cover fit on a 6.7?” Compatibility between these two engine components is a common concern. The 5.9 and 6.7 engines come from the same Cummins family, but differences exist. Understanding these variations helps ensure proper fitment and functionality.
Understanding the 5.9 and 6.7 Engines
Cummins introduced the 5.9-liter engine before developing the 6.7-liter version. Both engines power Dodge Ram trucks, offering durability and reliability. The 6.7 engine features improvements, including better fuel efficiency and increased power. However, these upgrades also affect parts interchangeability, including the valve cover.
Key Differences Between the 5.9 and 6.7 Valve Covers
Design modifications in the 6.7 engine changed several components, including the valve cover. The 5.9 valve cover has a different bolt pattern and overall size. While both covers protect the valvetrain, they do not share identical specifications. Truck owners must compare these aspects before attempting a swap.
- Bolt Pattern Variations – The 6.7 valve cover has a different bolt layout compared to the 5.9 version.
- Material Differences – Manufacturers adjusted materials for improved performance in the 6.7 valve cover.
- Breather System Updates – The 6.7 cover features an updated breather system, enhancing crankcase ventilation.
- Mounting Considerations – Engine geometry changes require precise alignment, affecting compatibility.
Will a 5.9 Valve Cover Fit a 6.7 Engine?
A 5.9 valve cover will not fit directly on a 6.7 engine without modifications. The different bolt pattern and mounting points prevent a direct swap. Engine components must align correctly to ensure proper sealing and function. Truck owners considering this swap should explore alternative solutions or modifications.
Possible Modifications for Compatibility
Some truck enthusiasts attempt modifications to fit a 5.9 valve cover on a 6.7 engine. However, these adjustments require careful consideration. Altering mounting points or drilling new holes affects durability and performance. Using an adapter plate or custom fabrication might provide a solution.
Best Alternatives to a 5.9 Valve Cover
Instead of modifying a 5.9 valve cover, consider using a 6.7-specific replacement. Aftermarket manufacturers produce performance-oriented valve covers for the 6.7 engine. These covers maintain proper fitment and function while offering aesthetic and performance improvements. Investing in the right component ensures long-term reliability.
Common Issues with Incorrect Valve Cover Fitment
Using an incompatible valve cover leads to various engine problems. Truck owners must consider potential risks before attempting modifications.
- Oil Leaks – Incorrect fitment results in poor sealing, leading to oil leaks.
- Ventilation Problems – The breather system design in the 6.7 engine differs, causing crankcase pressure issues.
- Reduced Performance – Improper airflow affects overall engine efficiency and performance.
- Increased Wear – Misaligned components accelerate engine wear and potential failures.
How to Choose the Right Valve Cover for a 6.7 Engine
Finding the right valve cover ensures optimal engine performance and longevity. Truck owners should consider several factors before purchasing a replacement.
- OEM vs. Aftermarket – OEM covers guarantee proper fitment, while aftermarket covers offer performance benefits.
- Material Quality – Durable materials prevent wear and extend component lifespan.
- Breather System Compatibility – Ensure the new cover aligns with the engine’s ventilation system.
- Ease of Installation – Choose a cover designed for straightforward installation without extensive modifications.
FAQs
1. Can I modify a 5.9 valve cover to fit a 6.7 engine?
Yes, but modifications require drilling, adapters, and precise alignment, which could lead to sealing issues and performance problems.
2. Are 5.9 and 6.7 valve covers made from the same materials?
No, the 6.7 valve cover features improved materials for better durability and performance compared to the 5.9 version.
3. What happens if I install an incorrect valve cover?
Improper fitment leads to oil leaks, ventilation problems, reduced performance, and increased wear on engine components.
4. Are aftermarket valve covers better than OEM replacements?
Aftermarket valve covers offer performance improvements, but OEM replacements guarantee precise fitment and long-term reliability.
5. Where can I buy a 6.7 valve cover?
OEM and aftermarket valve covers are available at auto parts stores, online retailers, and Cummins-authorized dealerships.