So my 02 S4 is losing coolant. if im driving it, it will go from max to min in about a day or two and ill have to refill. I recently brought it into the shop because of this and it started smoking really bad when shifting. never overheated and had heat always. yellowish mayonaise on the dip stick and under oil cap. We all thought it was the head gasket but when they started ripping the engine out, they found a ton of oil in the intercooler inlet pipe and the turbos were obviously shot. so i upgraded to Ko4's, 034 inlet pipes, etc. thinking this was the coolant issue. after 6 weeks in, i get the car back and im still losing coolant at the same rate, still no clearly visible signs of an external leak. yellowish mixture still forming under cap. waiting for a pressure test and they are optimistic its not a head gasket but im pretty sure it is. Im no mechanic by any means. still not overheating, still have good heat. not really seeing white smoke from tail pipes. its been cold so hard to tell. im thinking if its not the head gasket then maybe coolant flange or small leak only leaking when pressurized while driving but what else would cause that yellowish mayo mixture? any ideas? will this lead to new turbos going bad? will this cause "fuel cuts" when accelerating? i know i need a tune but need to get this done first.

 

Have you checked your axillary water pump? thats a common coolant leak area.

The foamy oil could be that your pcv system is on its way out. what your describing is what i see collected in oil catch cans. this is just a guess though.

 

Haven't checked the pump yet. Would that result in no signs of a leak and/or coolant mixing with oil? Or maybe there's just moisture getting into the oil