I'll start off by giving some background on my car, which is an 05' with 20k miles, and a Stage 2 Stillen Kit. Over the last couple of weeks, I notice my car would occassionally run a bit hotter than usual, at around 220 or so, and then fluctuate between 200-220 while street driving. But just today, the car started up at 220, and next thing I know, my temp gauge was completely at the top!

Fans are working, and there's coolant in the radiator. After I let the car cool down and took it for a spin, I blasted the heater and noticed it did take a little while before it actually blew hot air.

So after researching the overheating threads, I'm left with assuming the possibility of air bubbles or bad t-stat, although I'm having a difficult time understanding how either one of these can be the culprit, being that that car has such little miles, and I haven't messed with anything regarding the cooling system. But regardless, I want to attempt to bleed the system first, although a bit confused of the "correct" way to do it, as I've read several different methods people are using. And also, because I don't have the resevior tank (because of the Stillen kit), how to go about doing the refilling of coolant.

Help me out here, guys. I already freaked out over how hot the car got today, and not trying to let it happen again!

 

OOOPS!! Mods, can you please move this to the 350z section please??

 

You're in the 350Z section. I think you should try to bleed it but do a search for the factory manual on here and follow the instructions precisely as that worked for me the first time. Especially follow the slow filling part.
As for your lack of expansion tank, I would guess that you skip that step since I think I recall it's the final step. A better place for that answer would be the forced induction forum since you're on Stillen Stage 2. Just ask how to change coolant, though, to avoid flaming if they think you're in the wrong forum.

 

I can tell you that you will probably have to bleed the system more than once. Its a pia. You could pm superchargedg, he's had experience with all the silken kits. Gl

 

Was the car actually overheating? Maybe it's just the sending unit or the gauge.