I've been leery of forced flushes since reading the late Mike Soehnlein's
concerns at Wesfalia.org (
http://www.westfalia.org/community/showthread.php?284-Antifreeze-tech-notes-amp-maintenance-page-1
)
but also wanted to get as much coolant flushed out as possible.

I measured the volume drained from both engine block drains (only about 1/2
qt drained from the driver's side after draining the passenger's side).
 The specs for my 1.9L say the capacity of the cooling system is 18.4
quarts.  I drained 10.9 quarts, or about 59% of the volume.  I refilled the
system and ran the engine to operating temperature, then drained again.
 According to my calculations, at this point 83% of the old coolant was
drained out.  After repeating the procedure a third time, I'd removed 98%
of the old coolant.  Will all the the old coolant ever be drained out?  No,
that's mathematically impossible.  But 98% is pretty good and no special
tools are required, just a little patience.

Oh yeah, while I was at it I measured the temperature of the water that
drained out.  It averaged about 150 degrees.  This helped me diagnose the
low reading on my temperature gauge as the thermostat.

On Thu, May 10, 2012 at 11:55 PM, Alistair Bell <albell@shaw.ca> wrote:

> I understand and sympathize. I had difficulty getting it all out, even
> using a shop vac (with intermediate 20 l bucket). But I do think I got more
> out with the shop vac than when I did it without.
>
> alistair
>
> On 2012-05-10, at 8:15 PM, Rocket J Squirrel wrote:
>
> >
> > Clearly, I never drained anywhere near most of the old coolant.
> >
> > I am puzzled. Oh -- the heater valve was open.
>