Engine PCV Valve – Reliable Crankcase Vent Control for Nissan/Infiniti V8

This small valve is vital for clean running and long engine life. It guides blow‑by gases from the crankcase back into the intake to be burned, instead of letting them contaminate oil or escape to air. With correct crankcase ventilation, seals stay happier, oil stays cleaner, and fuel trims remain stable. ♻️

Why you need it

Proper ventilation keeps internal pressure balanced. That helps prevent oil leaks, sludge build‑up, and misfires. It also reduces emissions and improves idle quality.

How it works

Inside is a spring‑loaded plunger. Intake vacuum meters flow: small at idle, more at cruise. During throttle or a backfire, the valve closes enough to block reverse flow, protecting the crankcase and intake.

What happens if it breaks ⚠️

Stuck open: rough idle, lean codes (P0171),high oil use, oil in intake, whistling. Stuck closed: pressure rise, wet gaskets, dipstick lift, smoke, rich running (P0172). Hoses may collapse or crack.

Tech tips

Replace the grommet and check the breather hose together. Install upright, no sealant, snug only. A fresh valve restores smooth idle, cleaner oil, and steady trims.

Compatibility

• QX80
• QX56