CCV Filter Change on a 6.7 Cummins: What You Need to Know
The Closed Crankcase Ventilation (CCV) filter is one of the most overlooked maintenance items on a 6.7 Cummins diesel. Skip it long enough and you'll be looking at clogged intake systems, oil-fouled intercoolers, and a truck that runs noticeably worse. Here's how the system works, what the service involves, and what shapes how often and how complicated that service gets.
What the CCV System Does
Every internal combustion engine produces blowby — combustion gases that slip past the piston rings into the crankcase. Left unvented, crankcase pressure builds and damages seals. The CCV system routes those gases back into the intake so they're burned rather than vented raw into the atmosphere.
The problem with diesel blowby is that it carries oil mist and soot. The CCV filter — sometimes called a crankcase filter or breather filter — catches that oily mist before it can coat the intake piping, intercooler, and intake manifold. On the 6.7 Cummins (found in Ram 2500 and 3500 trucks), this filter sits in a canister housing, typically mounted on or near the valve cover.
When the filter clogs, crankcase pressure has nowhere to go. That forces oily air through the system unchecked, or it pushes out through gaskets and seals. Either way, it's a problem.
What a CCV Filter Change Actually Involves
The basic process on the 6.7 Cummins is straightforward:
- Locate the CCV housing — it's mounted on top of or near the engine, with hoses connecting it to the intake system
- Remove the hose connections from the canister (expect some oil residue — have rags handy)
- Unscrew or unclip the housing to access the filter element
- Replace the filter element and inspect the housing and o-ring
- Reinstall and check hose connections for proper seating
Most owners with moderate mechanical comfort handle this as a DIY job. The filter itself is a replaceable cartridge. Filter elements vary by model year and supplier, and prices generally range from roughly $30–$80 depending on brand and where you buy — though that can shift with market conditions.
The main complication most people run into isn't the filter change itself — it's the oil buildup inside the hoses and intake tract. If the filter has been neglected, there may be significant oily sludge in the intake piping that's worth cleaning out while you're in there.
How Often Should It Be Changed? 🔧
This is where things vary. Cummins has issued different service interval guidance across model years, and real-world conditions matter a lot:
| Condition | Typical Interval Guidance |
|---|---|
| Normal highway driving | Often 67,000–100,000 miles |
| Mixed city/highway | More frequent inspection recommended |
| Heavy towing or hauling | More frequent — increased blowby load |
| Older high-mileage engines | Inspect more often; wear increases blowby |
| Cold climates | Cold starts increase short-term blowby |
These ranges are general references. The actual Cummins maintenance schedule for your specific model year and application is the authoritative source — not forums, not generic interval charts.
Some owners inspect the filter at every oil change to catch problems early. Others follow the factory schedule. Neither approach is wrong, but a neglected CCV filter on a 6.7 Cummins is a known source of intake contamination issues, so this isn't a service item to ignore indefinitely.
Signs the CCV Filter May Be Due
- Excessive oil in the intake piping when you remove an intake hose
- Blue or white smoke at startup that clears after warmup
- Oil residue around the CCV housing or on connected hoses
- Rough idle or reduced power, though these symptoms overlap with many other issues
- Boost leaks if oily buildup has softened or fouled intake couplers
None of these symptoms alone confirm the CCV filter is the cause — a proper diagnosis requires hands-on inspection.
DIY vs. Shop Service
The CCV filter change is one of the more accessible diesel maintenance tasks. The job doesn't require special tools, and most experienced diesel owners complete it in under an hour.
That said, a few variables make it harder:
- Accumulated grime on an engine with high mileage or deferred maintenance can make hose clamps and fittings stubborn
- Damaged o-rings or housing cracks discovered during the job may require additional parts
- Intake cleaning, if needed, extends the job significantly
- Model year differences affect housing design and access — earlier and later 6.7 Cummins trucks aren't identical
If you're not confident in what you're seeing once you get into it, there's no shame in having a diesel shop complete the job. Labor time and cost vary by shop and region.
What Shapes the Outcome for Your Truck
Several factors determine how involved this service gets for any particular 6.7 Cummins owner:
- Model year — filter housing design changed across the 2007–present production run
- Mileage and maintenance history — a truck that's never had the filter changed at 150,000 miles is a different job than a truck serviced at regular intervals
- How the truck has been used — towing-heavy trucks see more blowby load
- Whether intake cleaning is needed at the same time
- Parts availability in your area and current pricing
The 6.7 Cummins is a durable engine, but its CCV system requires attention. How often, how involved, and what you find when you get in there depends entirely on the specific truck in front of you. 🔩
