I recently bought an '02 Passat TDi and was also intending to do all the fluids, for peace of mind. The coolant in mine looked OK, ie not obviously brown, but I discussed it with a reputable VW / German vehicle garage. Their opinion was that since it had G12 in from new he would not recommend changing it until the timing belt / water pump was due (about another 12 months for my car).
Obviously, because your coolant does look contaminated it would be wise to get it flushed, but the conclusion I came to was that even though the G12 is quite a bit more expensive it does have a seemingly proven ability to protect the engine for a loooong time, as opposed to the regular green stuff that should be changed every 2-4 years.
In the long run I feel that G12 would work out cheaper, especially if you intend keeping the car for at least four years or more.
Just my unqualified 2 cents worth
Obviously, because your coolant does look contaminated it would be wise to get it flushed, but the conclusion I came to was that even though the G12 is quite a bit more expensive it does have a seemingly proven ability to protect the engine for a loooong time, as opposed to the regular green stuff that should be changed every 2-4 years.
In the long run I feel that G12 would work out cheaper, especially if you intend keeping the car for at least four years or more.
Just my unqualified 2 cents worth
