Audiheavy

Working on son's 2006, A4, 2.0 with 115K on the clock. This all started with a rough running motor (rare 3-cylinder A4), turned out to be a burned intake valve with 0 compression in that hole. Pulled the head, all new valves and gaskets, back together with not too many issues. Car runs great, 185lbs across all 4 holes... after some break-in driving coolant tank full of chocolate milk. Possible seal failure between the oil filter housing/oil cooler where I'm forcing oil into the coolant system?

Thanks in advance!