More from Al Wick, whose first message I posted earlier this morning:

I got a couple other private messages regarding the same. I'll try to
clarify...

The crossover tube is the aluminum coolant tube that lives under the
intake manifold. It's rectangular in shape and the main coolant hose
attaches to one end of it. It's the one everyone reverses.
I'm unable to say there is a "best place" to add a fitting to the tube.
Likely it does not matter where you place the fitting. Just somewhere in
the top of this tube. The fitting needs to be on this cross over tube
because this is the highest point in the ENGINE cooling system. Your goal
is to purge any air that happens to be in the engine. This is different
than purging air from your radiator or from your heater core. Air in the
engine causes head warp. Air in other components just reduce their
efficiency. We imagine that air flows with the moving coolant, but
actually it only does to small degree.

Drill and tap this tube. Install a fitting, and run hose from that
fitting to your swirl pot. No dips in hose, it must gradually rise to
swirl pot. As long as the swirl pot is above the engine it will
automatically purge all air from the engine. This results in a "robust"
cooling design. Robust meaning it handles unusual conditions. If your
brother in law borrows your vehicle, blows a hose, and doesn't realize he
needs to bleed air, no problem. Because your system automatically purges
all air from engine.

Hope this is more clear.

-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

--
Sam Walters
Baltimore, MD

89 Syncro GL
85 Westy Weekender

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