No way of really knowing unless you have a transparent engine and can see what's going on inside.
MOST of the time, it is probably not necessary.
SOMETIMES, things aren't put together right and it is vitally important.
It's a cheap method of preventative maintenance for those 'SOMETIMES' cases.
You can install one and if you are only catching a small amount of oil in a few thousand miles, no harm no foul, and you can always take it off and sell it.
BUT, if you are a 'SOMETIMES', like me, catching 3-4oz of oil every 500 miles, you'll be glad you did and be thankful that you are not recirculating all that oil to be burned and carbonized in your combustion chambers.
Last edited by rmnc3r; 04-20-2012 at 01:55 PM.