One problem related to engine cooling system has been reported for the 1999 Audi A6. The most recently reported issues are listed below.
Water pump failed suddenly at 56,000 miles while on vacation trip. Car immediately overheated, and was not drivable without risk of serious damage to engine. Occurred several hundred miles from nearest Audi dealer. Cost to replace over $600 plus $400 for hotel & food for two nights (work performed by local vw dealer becuase nearest Audi dealer several hundred miles away; had to wait overnight for parts to come from Audi dealer; Audi USA will not warrany vw's canada's work, only parts, even though Audi is a subsidiary of vw). . Read more...