2005 Jeep Liberty yellow goop in filler cap

Hello

I change the oil every 3000k miles. Recently I noticed a yellow goop buildup on the cap and alittle in the filler houseing. I didnt notice any foam or discoloration in the oil that was drained. I recently replace the PVC value and 2 weeks later I noticed the yellow goop again. I heard a number of things that could be wrong: like scavenger hose blockage (not sure if my jeep has this hose), the oil I use is foaming up ( I use penzoil 5w-30), head gaket is leaking ( which I hope is not the case), I also heard it will go away once the weather warms up. I was hopeing you could give me a clearer answer. Thanks for your help