Understanding PCV's
 

Curious why my 2000 E250 w/5.4 motor basically has two crankcase relief provisions, one in each head or valve cover? The right/passenger side is the actual PCV running to the bottom back of the throttle body, left/driver side straight into a fitting just behind the throttle body. I'm curious as this particular engine has a huge accumulation of what appears to be oil sludge just behind the TB where it mounts to a 90* fitting on top of the intake.

The 90* Fitting:


https://cimg9.ibsrv.net/gimg/www.for...8a8326ac91.jpg

The accumulation:

https://cimg6.ibsrv.net/gimg/www.for...3d15c59413.jpg

I'll be adding an oil catch can on a reman'd 5.4 going into another van with the hopes of avoiding this sort of thing.

So my general questions are why only one PCV valve when there seems to be two outlets for blow by gasses?

Would my engine(s) benefit from having catch cans capturing oil and at least one PCV per engine?

Should I run both valve cover outlets through the catch cans before sending the gases back to their respective positions on the TB?

TIA! :-X22

The left/driver's side although it might appear to be vacuum is actually an air inlet to the crankcase. It taps into the TB (post air filter) so as to have access to filtered air instead of letting unfiltered air into the crankcase.

Okay---I get that--thanks!

So plumbing my soon-to-be-installed catch can should NOT include that inlet if I read this correctly?

BTW VERY useful info! :-X22

Yeah you don't want to do anything that's going to bypass the filtered air meant to go into the crankcase. :)

Got cha!

Thanks also for the lesson about the valve cover fittings---never paid that left side too much attention.