Hello All,
I just finished upgrading to an aluminum valve cover. Is there anything wrong with plugging the rear vent of the valve cover or does it need to be remain open? I don't want to create any leaks in the new gasket and cover.
hi, you need to run a line from that rear hole to your air cleaner breather filter, like stock. Do NOT plug that hole, it's how your engine breathes, along with the PCV in front. good luck, gz
One hole is fresh air in and the other is blowby out. https://www.youtube.com/watch?v=EPIfI9aZHt4
PCV takes the dirty air out and the other port lets fresh air in (unless you go EFI, then the PCV port becomes a CCV) If you only have one, you will either overpower the PCV and oil will be forced out the gaskets and/or blow the rear main seal or there will be too much suction and oil will be sucked out past the rings.