What's The Difference Between Oil/vapor Catch Can Systems?

CarMichael Angelo

clearly, I’ve got something going on in that hole
15 Year Member
Nov 29, 1999
Birmingham, al
All I know is mine sucks. The simplest of catch cans, I have a single -12 going into a 1qt? plastic catch can with a breather on top.

This piece of crap puffs every now and then,...the drain plug won't drain,..and because of where it is ( under the driver side fender) draining it is a pain in the ass.

So, if I buy another one of these things,..what do I look for? What will be different over what I currently have?
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Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
Box behind Walmart

Consider for a moment, the air velocity of the oil inlet tube. There may even be some way to measure it. All that oil kicks up, gets taken away by fast moving air to the catch-can, then gets sucked right to the bottom of the can where we hope it stops so that we can drain it in with the rest of our waste oil.

What if we doubled the diameter of of the entire path of oil vapor? We'd slow that air stream by half and probably pick up a lot less of the oil vapor. Some portion of that vapor would never make to the crank-case vent and instead, fall back into the pan.

Maybe look around in your bay and see if there's a good way to add a second PCV system. You might never have to empty that catch-can again. :shrug:


Double the capacity of the PCV system:

Decrease air velocity
Double the volume
Reduce crank pressures/increase ring seal
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