AudiWorld Forums - Anyone give feedback on my post-service question?

I have an '02 A4 1.8TQM

Had my car in for 50K service. Notes on the service info said that the coolant was tested out to zero (0) degrees and that the system should be flushed. So, I ask the service guy about the coolant supposedly being "lifetime" and never needing to be flushed per all the Audi propoganda. He shrugs and says thats not always the case.

So....I have yet to test the coolant myself to verify, but I trust more than dis-trust this dealer, they are pretty repuatable and do good work. Can anyone think of any other reasons why the coolant would degrade like this?

Car runs the same as the day she was driven off the lot, no problem with engine responsiveness, does not use oil (never have had to add oil between OCI's). Temp gauge reads the same as it always does. Just seems very odd that the coolant would turn sour without some other factor causing it, but I'm stumped on what else that cause could be?

Car had the radiator replaced under warranty at about 12K due to the upper part of the tank developed a crack, but no other coolant related work has been done except the occassional topping off done by the dealer.

Also, does our coolant require a special kind of coolant tester? I have a coolant tester that I have had for at least 15 years -- used it all the time in my '70 Mustang and Cougar when I owned them back in the day -- but coolant for those engines is different than what our vehicles use.

Any y'all thoughts on the coolant degradation and and proper testing tool, feedback and experience appreciated. TAI!