Does the bleeder valve discharge into the tank or on the ground?
 

I've never totally understood the bleeder valve. I know it's providing a path to get the air out of the front radiators when refilling the system but I don't know how it's plumbed on the outlet, or discharge side.

My new coolant tank holds pressure very well but I'm getting a coolant smell and a steam bath feeling around the rear of the car. I can't find a leak and there's no coolant on the garage floor. So I'm trying to think of anything that could be causing it and wondering about the bleeder valve. It's brand new because it's included when you get a new tank.

Is the tank cap one of the new revisions?
 

Was the system burped after the coolant level was refreshed?

Because it has multiple connections, technically it is on both sides, but because of where it is located height wise, that really does not matter. Have you considered a simple cooling system pressure test? In 15 min. or less, you would know for sure if the system is tight or not.

Thanks for the replies. A competent Porsche independent shop did the work. I'm sure he burped the system. No overheating by the temp gauge. The system is very pressurized after a drive in hot weather. It sounds like a soda bottle when I release the seal as I unscrew the cap (new style cap). It might not be pressurizing as much as a testing unit though.

Funny that it didn't smell for about 2 weeks after the tank replacement and the weather was brutally hot at the time. Most likely it's seepage on one of the concealed hose clamp connections. The coolant level seems up to the top all the time - no visually detectable loss. The smell and vapor seem to be concentrated exactly in the area where the work was done but no drips on anything I can see with a flashlight and inspection mirror and no drops on the floor. The shop also replaced the Tip coolant control valve, which had a vacuum leak so the coolant smell could be coming from there instead of the tank fittings. I can see he used new sections of rubber hose instead of reusing the 12 year old stuff. I'm pretty sure it's not simply the smell of residual coolant from previous leaks because I can feel the steam in the air.

I'll talk to the shop about a pressure test.

Why don't you just flip the bleed valve open & drive the car for a few days (or at least a few heating / cooling cycles) to get rid of any air bubbles in the system?
The pathetically vague temp gauge will not indicate the higher engine internal temperatures caused by air pockets
Getting rid of any existing bubbles is nigh on impossible without the bleeder valve being open - certainly not by undoing the pressure cap when hot.....