If all the things you say were done properly, you might have a head gasket leak. Have a compression check done to verify that. If so, budget about $1000-$1500 for a proper repair, since this is an Audi.
If all the things you say were done properly, you might have a head gasket leak. Have a compression check done to verify that. If so, budget about $1000-$1500 for a proper repair, since this is an Audi.