OK, here's the story.... TT was fine, perfect, absolutely rock solid stable, driving in all conditions.... then, the fan got a hold of the top radiator hose and wore a hole in it and it burst fluid.... wasn't a very violent one, more just a rub that finally wore through and starting spitting fluid... (I had noticed the hose was pretty close, but had been keeping tabs on it, no rubs, no issues.... then lost track of it for 200-300 miles and oops!) shut the car right down (could smell hot antifreeze as it got on the engine, etc, saw the fluid in the rear view and shut it off, maybe 15 to 20 seconds) as the temp gauge of course started to spike, but wasn't much of an issue as it was at 45 degree day, and I was at the top of the hill on the way to work, so shut the engine off and coasted it into the parking lot, temp needle never got above the next line to the right of top center.... put a new hose on right there in the parking lot, (note that the engine block was still full of fluid when I pulled the hose off) refilled the coolant, then ran the car in the lot at 1500-2000 rpm with the heat control on high and the blower on.. rechecked fluid, levels are good, etc... and now, the temp gauge behaves as follows: Start car, warms up fine and regular, temp rises to center as it always did.... can drive the car at highway speeds on flat terrain without any twitch or movement in the temp. However, try to climb a hill and the temp gauge will start running to the right pretty quick.... goes to the next line to the right, and if I push in the clutch and give it a couple of quick stabs on the gas pedal, it will start to ease back... Both fans work as they are supposed to, and everything seems normal, except for the fact that the temp gauge is now pretty squirrely from top dead center to next line to the right and back.... I have noticed however, that I will get coolant pushed back into the reservoir (boiling, bubbling, whatever you would like to term it,)..... it makes me think that I have an air bubble somewhere in the system.... I have removed the upper rad hose from the engine and poured coolant directly into the radiator via a funnel in the hose and it will push coolant back out the engine side with no issue, so there does not seem to be a blockage. I have also elevated the reservoir and loosened the heater hose at the high point of the system, stuck a drill bit in between the wall of the hose and the inlet at top dead center and tried to bleed the system out that way as well.... getting water up there fine and dandy, and made a mess on the floor.

Tonight I pulled the upper rad hose back off and started from scratch. Refilled reservoir, put heat on high, no blower this time, seemed to circulate just fine.... drove car around here locally and it did fine as long at it was on flat ground (probably 7-8 miles at village speeds, 30-45 mph).... then ran it up a small hill.... light incline, not steep, it went up twice pretty rock solid with very little fluctuation in the temp needle.... third time up the hill, the needle headed to the right.... let it go one line to see if it recycled back.... not this time... tried pushing in the clutch and giving it a couple light revs to see if it would circulate down..... no dice...... continued to climb, so shut it down... let it cool off (hood open, about 15 minutes), then was able to start it up, temp returned to top dead center, turned the car around, made it a half mile tops, and the needle started climbing again..... shut it down.... opened hood and let it cool again for about 15 minutes.... was able to get it the 2.5 miles back to the house after that and pulled in the driveway at top dead center.... it really makes me think I have an air bubble somewhere, but just cannot seem to get it bled..... what am I doing wrong?

Note that the fans do work just as they are supposed to, there has been no check engine lights, warnings, etc.... no fluid leaks, no unexplained "lost" fluid.... fluid level stays perfect, except when it gets hot and it pushes fluid back into the ball, then the ball will get 5/8 - 3/4 full.... and I can only really get the temp needle to move around when climbing hills.... and not huge hills either.... light incline stuff will do it... in fact I am actually hesitant to attempt any "real" hills..... really stumped on this one..... help?

 

Other notes, this is a 2001 180hp TT quattro, 5 speed. It has 112k, with the water pump (metal impeller) and timing belt just redone at at 103k. I do have the green cap as well.