That is codsendation build up ,the dodge engines do it when the temp gets really low .The plastic filler tube is cold and lets it build up .When the temp gets around 50f or so it should not be noticable.We call it snot buildup.
The hemi is a push rod engine with mds that requires 5w20.The 4.7 is a single overhead cam engine with no mds and uses 5w30. If you are under warranty I would use caution.