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Old 02-12-2011, 06:58 AM   #4
Dale_K
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Join Date: Dec 2010
Location: Hot Springs Village, Arkansas
Posts: 245
A long time ago I was a licensed plumber and worked on many hydronic heating systems, including their expansion tanks and air separator valves. I guess that experience adds to my confusion of the Boxster system. The large hydronic heating plants have a specialized fitting that swirls the fluid inside like a little cyclone. The air is lighter and stays in the center and at the top of the center of the fitting is a discharge line that leads to the expansion tank(s). That line is left open all the time and you get air out of the system by venting the expansion tank. But I digress.

Say there was no separate bleed valve on the Boxster. A tee fitting on the highest coolant hose directs a new hose into the bottom of the expansion tank. It seems to me such a system would work (as it does on my Corvette). Think of the Boxster bleed being open all the time with the discharge line plumbed into the pressurized plastic tank.

I'm not trying to argumentative. I enjoy thinking through why engineers choose one solution over another and I want to understand why Porsche used the design found on our cars. Especially since I've never seen it on any other car I've owned.
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