ADD W1 Patented Check Valve 
(US D1.073.740S)

Upgrade your crankcase ventilation system with the ADD W1 Check Valve, designed to prevent backflow, stabilize pressure, and protect your engine under all driving conditions. This is a must-have upgrade for any oil catch can setup, especially for turbocharged or supercharged applications.

Valve Options:

Standard Check Valve (NA Only)
• Designed for Naturally Aspirated (NA) engines
• Basic one-way airflow control
• Not compatible with turbo or supercharged systems

PRO Check Valve (Recommended Upgrade)
• REQUIRED for Turbo & Supercharged engines
• Supports high boost applications (0–100 PSI)
• Ideal for heavily modified performance builds
• Also compatible with NA engines for improved performance and reliability

Kit Includes:
• (1) Aluminum Check Valve (Standard or PRO)
• (2) Worm Gear Clamps
• Durable anodized aluminum construction

Why You Need a Check Valve:

When the factory PCV system is removed or modified, boost pressure can enter the crankcase, causing excessive pressure buildup and potential engine damage. The ADD W1 Check Valve prevents reverse airflow and protects your engine by maintaining proper pressure control.

This upgrade is highly recommended when installing aftermarket oil catch cans or modifying your PCV system.

Installation Options:

✔ Catch Can Setup:
Install the check valve on the outlet side of the oil catch can (V1, V2, V3). The valve ensures airflow moves away from the catch can, preventing backflow into the PCV system.

✔ Vacuum Line Setup:
Can be installed inline with vacuum or boost lines to prevent reverse airflow. The valve opens at just 0.25 PSI in the forward direction and blocks pressure in reverse.

Compatibility:
• Works with ADD W1 catch cans (V1, V2, V3)
• Compatible with other aftermarket catch cans
• Ideal for turbocharged, supercharged, and modified engines

PRO Tip:
If you are running boost, upgrading to the PRO Check Valve is not optional — it is required to prevent crankcase pressure issues and ensure long-term engine reliability.