My engine temp climed steadily when I was idling, it got over the 100C mark (the mark before the red/white 120C line). I turned the heat on all the way and it came down quickly, but I don't like this much fluxuation in my temperature. I have a brand new radiator and aux coolant pump (yes that climate control blows HOT!)

But I am willing to bet it's the thermostat maybe? I have been wanting to put some water wetter in, but I won't if I have to change something out and drain the system ya know.
I also have a question about engine clicking, I notice while I was idling with the windows down and cd player off that there's a clicking that comes and goes, it does it when it's idling, it does it all the rpm's up to 1500 rpm and it goes away at 2000. It almost seems regular in pattern. Lifter out of adjustment maybe? Any thoughts? Greatly appreciated.
Thanks in advance guys.