My 1995 S6, 5 cylinder 20V turbo engine with about 85,000 km, is mysterously losing about hald a liter of coolant every week. THere are no signs of coolant leakage around the engine block or plumming. One other symptom that I exerience is that it will misfire for about a minute on most cold starts. Checked the engine oil and it's not contaminated. The coolant resevoir does not have oil in it, but there seems to be some traces of carbon deposit. Otherwise, the engine runs fine. What are the typical symptoms of a blown head gasket for an Audi. Do I have a blown head gasket? If not, what do you make of my symptoms?