I have a 2011 Outback 2.5i. I live in a hot dry climate and there has always been heavy condensation but last summer it was water, this summer I have noticed a small ring in my garage and the consistency of the residue is neither water or oil, but something inbetween. I took a sample on a paper towel and it is somewhat brown with no odor. Mechanic at dealership said heavy condensation with some residue is normal. Any suggestions.