Does a 5.9 Valve Cover Fit n a 6.7 – The Ultimate Guide!

Does a 5.9 Valve Cover Fit on a 6.7 – The Ultimate Guide!

I tried fitting a 5.9 valve cover on my 6.7 Cummins, but the design and sensor placements didn’t match. Compatibility is key to avoid installation issues.

Does a 5.9 valve cover fit n a 6.7 Cummins? No, because the design, sensors, and gasket are different. Using the right cover is important for proper performance.

Stay tuned with us as we explore the question, ‘Does a 5.9 valve cover fit n a 6.7?’ We’ll break down the details and share everything you need to know!

5.9 vs. 6.7 Cummins – Which Diesel Engine Is Right for You!

Does a 5.9 valve cover fit n a 6.7, The 5.9L Cummins, introduced in the late 1990s, became an instant favorite for its simplicity, reliability, and robust performance. Its successor, the 6.7L Cummins, launched in the mid-2000s, brought modern improvements to meet stricter emissions standards and enhance power and efficiency. To fully understand why a 5.9 valve cover may or may not fit on a 6.7, we must first examine the primary differences between these engines.

5.9L vs. 6.7L Cummins – The Ultimate Guide to Diesel Engine Differences!

Displacement and Design:

5.9 Cummins: With a displacement of 5.9 liters, this engine is known for its straightforward design and fewer emission-related components.

6.7 Cummins: Featuring a larger displacement of 6.7 liters, this engine incorporates advanced systems such as a Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) for cleaner emissions.

5.9L vs. 6.7L Cummins – The Ultimate Guide to Diesel Engine Differences!
source: bostechauto

Emissions Control:

5.9 Cummins: Minimal emissions components, making it easier to work on and modify.

6.7 Cummins: Equipped with modern emissions controls, requiring additional components that impact part compatibility.

Crankcase Ventilation:

The 6.7 Cummins features an integrated crankcase ventilation (CCV) system built into the valve cover, whereas the 5.9 Cummins uses a simpler design.

Physical Dimensions:

While the two engines appear similar in size, the 6.7 Cummins incorporates additional components that make its valve cover slightly larger and more complex.

Valve Cover Design – 5.9L vs. 6.7L Cummins!

The valve cover plays a crucial role in engine operation, housing components like the rocker arms and valves while also protecting these parts from debris and contaminants. Does a 5.9 valve cover fit n a 6.7, However, the design differences between the 5.9 and 6.7 valve covers make compatibility a challenge.

Key Features of the 5.9 Valve Cover:

  • Simpler design with minimal sensor ports.
  • Straightforward gasket layout.
  • No integrated crankcase ventilation system.
  • Compact and lightweight.

Key Features of the 6.7 Valve Cover:

  • Larger size to accommodate modern emissions components.
  • Integrated crankcase ventilation system with sensor ports.
  • More complex gasket design for a tighter seal.
  • Additional mounting points for advanced sensors and hoses.

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5.9 vs. 6.7 Cummins – Why Their Valve Covers Aren’t Interchangeable!

Design and Fitment Issues

The 6.7 Cummins valve cover is specifically designed to accommodate the larger displacement and advanced components of the engine. Does a 5.9 valve cover fit n a 6.7, Attempting to fit a 5.9 valve cover onto a 6.7 engine would result in alignment issues and improper sealing.

5.9 vs. 6.7 Cummins – Why Their Valve Covers Aren’t Interchangeable!

Sensor Incompatibility

The 6.7 valve cover includes additional ports for sensors such as the crankcase ventilation system and oil pressure sensors. These ports are absent on the 5.9 valve cover, rendering it incompatible with the 6.7’s electronic systems.

Gasket Differences

The gasket on a 6.7 valve cover is more complex to account for the additional components. A 5.9 gasket cannot create the proper seal on a 6.7 engine, increasing the risk of oil leaks.

Emissions System Constraints

The 6.7 Cummins integrates its emissions control systems directly into the valve cover, whereas the 5.9 Cummins does not. This fundamental design difference makes the two parts incompatible.

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Alternatives to Swapping a Valve Cover – Save Time and Money!

If you’re considering replacing or upgrading the valve cover on your 6.7 Cummins, here are some better alternatives:

Aftermarket Valve Covers

Explore aftermarket valve covers specifically designed for the 6.7 Cummins. These options often feature:

  • Improved crankcase ventilation.
  • Sleek, polished finishes for aesthetics.
  • Enhanced durability and heat resistance.

OEM Valve Covers

Stick with Original Equipment Manufacturer (OEM) valve covers to ensure proper fitment and performance. OEM parts are designed to meet Cummins’ exact specifications.

Custom Modifications

If you’re set on using a 5.9 valve cover, consider custom fabrication. However, this process is time-consuming, expensive, and may void engine warranties.

Alternatives to Swapping a Valve Cover – Save Time and Money!
source: cummins

Comprehensive Comparison Table – Key Differences Simplified!

Feature5.9 Valve Cover6.7 Valve Cover
Size and DimensionsCompactLarger, accommodates emissions
Sensor PortsMinimalAdvanced, includes CCV ports
Gasket ComplexitySimpleComplex for tighter seals
Emissions IntegrationNot includedIntegrated into design
Compatibility with 6.7NoYes

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Frequently Ask Questions 

Can I modify a 5.9 valve cover to fit a 6.7?

While technically possible with extensive custom work, it is impractical due to the significant design differences and high cost.

What are the best aftermarket valve covers for the 6.7 Cummins?

Look for brands like BD Diesel, Pusher, or Fleece Performance, which offer durable and performance-oriented options.

What happens if I use the wrong valve cover?

Using an incompatible valve cover can lead to oil leaks, sensor malfunctions, and engine performance issues.

Conclusion

The 5.9 valve cover and 6.7 Cummins are products of different engineering generations. While they share a legacy of reliability, their valve covers are not interchangeable due to significant differences in design, sensor placement, and emissions requirements. For the best results, always use a valve cover designed specifically for your engine model.

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