On Sun, Apr 28, 2013 at 7:01 PM, Tom Carchrae <tom@carchrae.net> wrote:

> Today I put all the fluids back in their places (ie, emptied overflow tank,
> re-bled system) and for curiosity, I took off the small hose between the
> expansion tank and the overflow tank.  It happened to be the same size as
> the hose I use to bottle beer, so I stole a bit and replaced it - a
> temporary fix, I will replace with proper heater hose.
>
> The old hose definitely had holes in it; I tested by partially submersing
> it in water.  The new hose is airtight - and clear - and I saw how it
> sucked fluid up from the overflow tank when the engine started.

That last part seems backwards.  When the engine is started and is getting
warmer, the expansion of the coolant in the system should force liquid or
gases, whatever is at the top, out of the pressure tank and toward the
overflow tank.   When the system is cooling down the coolant should be
sucked from the overflow tank.

Have you tested your pressure cap?

Larry A.