oil cap

I removed the oil fill cap today and noticed it had some condensation and alittle milky looking,dip stick was clean,is this just normal buildup on a 3.8,also do alot of these 99 pa rust along the bottom of the door where the rubber seals are,it seems like they collect dirt and salt and it just stays there.Will take them off this spring and clean under them,anyway the only rust I have including the underside is on the lower doors

You have a coolant leak somewhere and I would suspect the UIM. Do not drive the car until this has been diagnosed, otherwise you will need a new engine