Ajhsys@aol.com wrote:
>
> In a message dated 8/27/02 11:31:39 AM Eastern Daylight Time, mgbob@juno.com
> writes:
>
> >
> > Is it true that ethylene glycol raises the boiling temp and lowers the
> > freezing temp, but decreases the rate of heat transfer from iron to
> > coolant to radiator?
>
>
> The BEST heat transfer from coolant to metal is obtained by using pure water.
We went through this massive debate a couple of years ago in Australia
when the motorsport regulartory body, CAMS, put the issue up for
discussion when they were contemplating banning glycol-based coolants
from competing vehicles.
The reason behind this was that cooling fluid losses on racetracks
happened more frequently than was being noticed and/or acknowledged and
was either more difficult to handle than - or just wasn't being handled
as well as - other fluid spills such as brake fluid, oil, etc. It was
usually a case of ... "it is just coolant, it will evaporate so no need
to clean up the spill". Well, the water evaporated fine, but this left
a slippery glycol residue which was especially noticed by motorbike
riders using the same tracks.
So the technical argument arose that there would be no harm in banning
glycol-based coolant because pure/plain water worked as well if not
better in competition vehicles.
In the end it all got too hard and they didn't ban the coolants but I
think much of this came from people in club competitions who put their
street cars on the track and who didn't want to have to drain and flush
the coolant out of their radiators before each event and then replace
the coolant once the event was over. But, a lot of useful discussion
and information came out of the debate in the meantime.
And the main point to arise was as stated "The BEST heat transfer from
coolant to metal is obtained by using pure water".
Eric
--
Eric
'68MGB MkII
Adelaide, South Australia
"Nothing overshadows truth so completely as authority"
ALBERTI
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