MustangWorks.com : Ford Forums - View Single Post - Is a valve cover breather bad for the 4.6????

mlambrecht82 · 08-21-2003, 05:24 AM

DON'T PLUG UP THE HOLE ON THE VALVE COVER!!! This is what relieves your engine of all the blow-by vapors. You can go buy a universal fit one at AutoZone or Kragen for $8 or so. It has a rubber base and will slide over the plastic piece in the valve cover. The breather filter will not hurt anything, air flows through it only at cruising speed where vaccum is around 10" HG. Under load or at idle the PCV valve is closed. I've had the breather cap on mine for a while now, and no problems. The MAF senses air after the breather inlet. Just don't disconnect it from the passenger side of the engine where it goes into the intake manifold.

08-21-2003, 05:24 AM	#6
mlambrecht82 Registered Member Join Date: Oct 2002 Location: Fresno, CA Posts: 101	DON'T PLUG UP THE HOLE ON THE VALVE COVER!!! This is what relieves your engine of all the blow-by vapors. You can go buy a universal fit one at AutoZone or Kragen for $8 or so. It has a rubber base and will slide over the plastic piece in the valve cover. The breather filter will not hurt anything, air flows through it only at cruising speed where vaccum is around 10" HG. Under load or at idle the PCV valve is closed. I've had the breather cap on mine for a while now, and no problems. The MAF senses air after the breather inlet. Just don't disconnect it from the passenger side of the engine where it goes into the intake manifold. __________________ _________________________________ 04 Cobra densecharger CAI BBK off road X pipe Custom Electronic Exhaust cut outs Tuning via Diablo Predator Ported and polished Throttle body and plenum Line locker (for the smoke shows) Stock boost 412 rwhp 379 rwtq