foamy oil in valve cover

2001 5.4, 4x4, 126,000.  Rt side valve cover gets heavy foam deposits like there is excessive water in the oil.  Only happens in rt. valve cover,  crankcase oil is clean.  This only happens when the air temp falls below 65.  Also have a lifter/rocker arm on same side that knocks until warmed up, this also happens only when temp is below 65.  Once engine reaches operating temp the noise goes away.  Acts like hydraulic lifter not pumping up.
Very puzzled by the foamy oil only in this location.  Does anyone have ideas on this?

ck all crankcase venyilation and pvc valves

PCV totally shot.  Replaced valve and put some SeaFoam in oil to dry the condensation.  Also ran SeaFoam through throttle body.  We'll see if it clears up the condensation, it at least has better throttle response now.