About a week ago I noticed my coolant tank level was a bit low, I check mine about once a week just to make sure there are no issues. My car is an 07 Z51 A6 DD with about 128,000 miles on it. The car has been remarkably trouble free and has only required regular service and maintenance items. Spark Plugs, Ign Wires, Belts, Brakes Tires, fluids etc.
I added about a quart of coolant, A quick check of all hoses and possible leak sources revealed nothing, no coolant on the ground, no wet water pump, no contaminated engine oil, nothing. So I drove it back and forth to work for a couple of days and sure enough on the 3rd day I noticed the level was again down, this time up by the drivers side upper radiator shroud, I noticed a couple of drops of coolant that looked like it had splashed there, put since I know I wiped everything up, these drops were new, so after removing the upper radiator cover, and starting the engine, after about 5 minutes of running, sure enough a few drops of coolant appeared from one of the upper radiator tubes where it connects to the header tank, it's a very small leak and looks like a fatigue crack on the tube since there is no sign of any foreign object damage.
Removing the radiator was not that bad considering there is not a lot of room. The coolant that I drained was clean and clear, as is the inside of the old radiator, no build up or deposits and nothing out of the ordinary, I ordered a new radiator, new hoses and a belt since they are the originals and I have them off any way. The original hoses still appear to be in good condition so its more peace of mind than anything, I guess nothing lasts forever and I don't think it really owes me anything. The new radiator, hoses, coolant, and belts are all in and the car is back on the road. Only took a few hours to do it all so not a bad day after thanksgiving job.

 

Nice job!!

 

Awesome! Peace of mind is a great thing!