An LLY CCV reroute kit package is a simple but effective crankcase ventilation upgrade designed for 2004.5–2005 6.6L Duramax LLY engines. Its main purpose is to redirect oil vapor and blow-by gases away from the intake system, helping reduce carbon buildup, improve turbo cleanliness, and support long-term engine reliability.

On the factory LLY setup, crankcase gases are routed back into the intake tract. Over time, this allows oil mist to enter the turbo inlet and intercooler piping, which can create sludge, reduce airflow efficiency, and increase maintenance needs.

What Is an LLY CCV Reroute Kit Package?

An LLY CCV reroute kit package is a bolt-on system that replaces or modifies the factory crankcase ventilation routing. Instead of sending oily vapors into the intake, the system redirects them through a hose or vent line away from the turbo system.

Most packages typically include:

• Reinforced CCV reroute hose
• Intake block-off plug or cap
• Hose clamps and fittings
• Valve cover adapter connection
• Optional catch can compatibility parts

The design is simple, making it one of the easiest Duramax upgrades to install.

How the Factory LLY CCV System Works

In the stock LLY Duramax engine, crankcase pressure is created by normal engine blow-by. This pressure is vented through the CCV system and routed back into the intake.