I checked with the boat yard this morning. It was Panol that they
sold me. They use it straight for winterization only. It may freeze
into a slush but won't expand and isn't a problem for a system that
isn't running so that it has to pump the stuff around.

The straight RV stuff , without corrosion inhibitors, says "No Mixing
Required" right on the bottle.

--

Roger Long



"Rich Hampel" wrote in message
...
50% ethylene glycol and 50% water will take you down to -20degrees
F.

100% antifreeze 'probably' (no guarantee) wont harm the block
because
just about all substances on earth get smaller when they get colder.
Water is an exception however and becomes less dense and 'larger' at
near its freezing point; hence, the need to add antifreeze, .....
the
getting 'larger' produces the pressure to break castings, etc.

Incidentally ---- If water didnt have this 'little quirk' property,
all
the ice in the ocean would fall to bottom of the ocean, never thaw,
and
the highest ocean temperature in mid summer (thawed surface ice)
would
be only 4 degrees Celsius .... and there wouldnt be much life on
earth.
Be very thankful that frozen water floats.

Looks like you should drain the antifreeze, add water (the mix
ratios
are usually listed on the side of the container) and reinstall.to be
absolutely safe.



In article , Roger Long
wrote:

"Rich Hampel" wrote in

100% antifreeze will freeze as solid as a brick.


Yikes! Will it freeze hard enough to crack an engine block or is
it
just like salt water slush? The yard service manager who told me
how
to winterize the engine didn't say anything about mixing it with
water.