I have a 2000 NB 2.0L that is overheating. I have replaced the thermostat and now it is still overheating, just not as often. Before I replaced the thermostat the heater worked; now it does not, and there seems to be circulation because the top radiator hose does get hot and pressure is created. When I have been driving it I have been leaving the heater on full to hopefully get it to work, and at times I will hear something try to kick on, kind of like the AC compressor but not as dramatic, and the heater starts to heat up a little then quickly after it goes back to cold. I have heard that these cooling systems are notorius for getting air bubbles in them, so I have been trying to see if I can get them all out but I have no idea if I am really doing anything. :banghead: When I get it really warmed up and I turn off the car I hear a bubbling boil sound as well. I am pretty new to the watercooled cars I have driven and worked on a aircooled Beetle for 7 years and water is new to me. If any one could help that would be great. Thank you.

water pump is bad... i reccomend an aftermarket METAL impellar one from www.ecstuning.com

Replace the timing belt at the same time. The pump fails because it has a plastic impeller and is very very common! Do a search on "how to"