The crankcase ventilation (CCV) filter separates oil from blowby gases before they are vented or recirculated, and a clogged one causes crankcase pressure and oil residue.
What it does
Modern diesels route blowby from the crankcase through a CCV filter that traps oil mist. This keeps oil out of the intake and controls crankcase pressure. Over time the filter saturates with oil and must be replaced as routine maintenance.
Signs it is failing
- Oil residue in the intake or around the breather
- Increased crankcase pressure or seal seepage
- A clogged, saturated filter element
- Whistling from the breather system
Replacement and what to know
The CCV filter is a scheduled maintenance item and is straightforward to replace. Use the correct filter for your engine and replace it on interval; a neglected filter lets oil into the intake and can raise crankcase pressure enough to push seals.
Frequently asked questions
What does a CCV filter do?
It separates oil mist from crankcase blowby so oil stays out of the intake and crankcase pressure is controlled.
How often should I change it?
It is a scheduled maintenance item; replace it on your engine's interval, sooner if it saturates with oil.
What happens if it clogs?
Oil residue reaches the intake and crankcase pressure rises, which can push oil past seals.
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