2002 dodge 4.7 Engine sludge

I have a 2002 dodge ram 4.7. When I open the oil filler cap it is filled with white crap, sludge I guess. I always change my oil every 5000 kms. Just wondering if anybody else had this problem, and what I can do to fix it? I am going to remove the PCV valve and clean or replace it. Should I use seafoam or anything ? or should I just live with it, as I have heard it is a chronic problem for these engines.