2004 Audi A6 SMOKE

Well when you idle the engines vacuum is at its strongest, And white smoke is an indication of coolant burning in the combustion chamber, what I am thinking is, the intake manifold is faulty, and when you idle the vacuum is so strong that it is pulling coolant into the combustion chamber. To be sure that the manifold is the problem area, have the system pressure checked, this will help locate the compromised area(leaking area).
Thanx
jody

Yes, there should be a pcv valve at the back of the intake manifold, and remember it only takes takes very small amounts to cause this unless there are huge gusts of non stop smoke coming out.

Check the brake fluid too, sometimes a faulty valve will allow brake fluid to be vacuumed into the system

Check the brake fluid too, sometimes a faulty valve will allow brake fluid to be vacuumed into the system.