Hi Scotty, I just picked up a used 2009 Chevy Aveo5 LT for commuting and noticed a hissing sound from the valve cover and a misfire at idle. I read that it could be a stuck open PCV so I replaced the valve cover and gasket and now the misfire is gone but the car is leaking a ton of oil from what looks like the rear main seal. What did I do wrong, could my new valve cover have a defective PCV? Thanks.
the pcv system could be blocked elsewhere. I don't have a diagram on me, but there might be a pcv valve on one valve cover, and a breather on the other. Then theres all the tubes connecting them to the intake. Inspect all of it.
If it’s leaking heavy now but wasn’t before I would think you possibly pinched the valve cover gasket putting it on and most of them require some sort of sealant at least on the corners or wherever it might be raised. It’s a simple mistake but I would look all around that valve cover to see where it’s coming from
I always use a new PCV valve when I do an oil change. It's cheap insurance. If it clogs, pressure build up in the crankcase will blow out the main seals. Ask anybody who has an oil catch can who forgot to drain it.
