CCV: What It Is and Why It Exists
What Is CCV?
A crankcase ventilation system relieves pressure in an engine’s crankcase by collecting blow‑by gases and routing them through a separator before sending cleaned vapors back into the intake tract. CCV replaces open‑vent designs to prevent oil leaks and control emissions.
Regulatory & Technical Origins
Closed systems began appearing in the 1960s for passenger cars to meet California’s early smog laws, then expanded across all vehicles under 1968 federal emissions regulations. Diesel‑specific CCV filters emerged in the early 2000s as manufacturers and regulators targeted particulate emissions from blow‑by gases, with companies like Racor introducing dedicated CCV filtration in 2003.
Why Crankcase Ventilation Is Essential
- Pressure Relief: Without ventilation, blow‑by raises crankcase pressure, damaging seals and gaskets and causing oil leaks.
- Oil Dilution: Unburned fuel condenses in the oil, reducing its lubricity and accelerating wear.
- Water Contamination: Combustion water vapor condenses, emulsifies oil, and forms sludge that risks bearing and seal damage.
By coalescing oil from blow‑by, CCV systems return oil to the sump and redirect cleaned gases into the intake for combustion, preserving both engine internals and the environment.
Why Diesel Owners Choose CCV Delete or Reroute Kits
How Stock CCV Fails
Although designed to protect, factory CCV separators often clog with oil, soot, and debris. In diesels, blow‑by carries soot particles from EGR systems and particulate filters, mixing with oil mist to form varnish and sludge in hoses and filters.
Common Symptoms of a Clogged CCV
- Oil Leaks at Seals: Excess pressure forces oil past crankshaft seals and gaskets.
- High Crankcase Pressure Codes: Diagnostic Trouble Codes(DTC) appear on the dash.
- Turbo Lag & Noise: Sludge on turbo vanes disrupts airflow balance, causing lag, whine, and bearing wear.
- Poor Intercooler Performance: Oil fouling on intercooler cores raises intake temps and saps power.
- Dirty Intake: Visible oil sludge accumulates in intake plumbing, requiring regular disassembly.
- Blue Smoke: Oil vapor re‑enters cylinders, burning with fuel and producing blue‑tinted exhaust.
Top Benefits of Deleting or Rerouting Your CCV System
Clogged CCV reduces volumetric efficiency—blocked hoses and buildup starve cylinders of fresh air, hurting fuel economy and power. Oil‑soaked components accelerate wear on turbos, sensors, and valves, compromising longevity and reliability. Next, I’ll explain the benefits you’ll gain by deleting or rerouting your CCV system.
Cleaner Intake & Reduced Oil Residue
A reroute kit with external catch can or bypass lines isolates and drains oil away from the intake, keeping intercoolers, intake manifolds, and turbos free of varnish and sludge.
Lower Engine Bay Temperatures
By eliminating hot, oil‑laden vapors from the intake and valve covers, ambient engine compartment heat drops—protecting wiring, hoses, and sensors.
Enhanced Turbo & Intercooler Life
Keeping oil out of the turbo inlet prevents vane sticking and imbalance, extending turbo bearing life and maintaining boost responsiveness.
Simplified Maintenance & No More Messy Hoses
A well‑designed reroute or delete kit uses smooth, direct plumbing and an accessible catch can, reducing the need for periodic intake cleaning and hose replacements.
Cost Savings
Fewer oil leaks and component failures translate to lower repair bills. Avoiding frequent intercooler or turbo replacements—and reducing shop labor for CCV maintenance—saves money over the life of the truck.
Legal & Environmental Considerations
While CCV reroute kits improve reliability, venting any unfiltered crankcase vapors to atmosphere can violate local emissions laws. Proper reroute kits recirculate filtered gases back into the intake. Always verify your state’s regulations before installing a delete kit, and consider reusable catch cans that meet CARB evaporative emission standards for off‑road or racing use.
