2KS4GR

Hello all new to forum. Wanted to now who has had same syptoms. My 2000 S4 has been running warm for a few weeks. I have replaced the temp sensor although it already had the updated green sensor. I figured for a few dollars I wanted to be sure the temp was correct. Found the gauge was correct. A few times it got hot enough to turn the aux fan and after run coolant pump after turning car off from a short drive. Surge tank is hot and it has good heat. It does run much cooler if the defrost is turned on. This forces the electric fans on, as well as exchange heat thru the heater core. This made me suspect bad fan clutch, like the radiator was not exchanging heat efficently. Fan clutch was definately questionalble. Replaced fan cutch. Definately noticed a huge difference in air flow thru radiator and around motor at idle. Thought all would be well. Wrong! What could it be? Bad head gasket, water pump, Turbo near death? Ugh! I don't think it is the water pump as the heater works well and the surge tank temperature tracks along with the coolant temp gauge. As a test I ran the heater after shuting the engine down and it went from blowing super hot air to cold in less than 30 seconds. I would think the the T-STAT would stick open not closed if it went bad. If anyone has had a water pump go, what were your syptoms? Likewise for head gasket leak. I do not have abnormal turbo noise or noticable coolant loss. I do smell coolant from time to time in engine compartment. Any help Appreciated. Thanks

quickaudi:STFA

you could have a blocked radiator, at least partially, or a clogged line. does the radiator feel hot on one end and cooler on the other?