Techtip25

SAVVA Technical Tips - no 25

Water additives.

Here is another suggestion on the use of water additives from Robin Phipson. Robin seems to know
what he is talking about, however, draw your own conclusions. This product is
freely available from most accessory stores.

To Quote:

Hello Eric,

I read your query WRT cooling system additives which protect against corrosion,
but do not contain anti-freeze, and respond as follows:

The product is AQUACLEAR.

It is available from many spares shops, and is very reasonably priced at around R18-00 per bottle.

100ml treats 10 litres, which is sufficient for most cars. It provides total corrosion
protection for all types of engine.

I have been using it for many years, both in our own cars and in customers' cars, both
modern and ancient. It really works.

99,9% of motorists are unaware of just how bad anti-freeze is, especially for older cars:

- Many anti-freezes actually INCREASE corrosion if the concentration is below 30%. Who
puts in 30% or more?

- Most cheap anti-freezes are heavily diluted when still in the bottle, thus making it
impossible to make a mixture of the desired/correct concentration.

- Anti-freeze (ethylene glycol) has terrible "creep-seep" properties, which often causes it
to ooze out between head and other gaskets, hoses etc on older cars. This can cause it to run
into the engine oil in small quantities. Ethylene glycol and engine oil mixed together form a potent
wear medium, which the hapless owner is usually quite unaware of.

- Any mixture of ethylene glycol and water drastically reduces the heat transfer from combustion walls
to coolant, and from coolant to radiator tubes compared to water. The more the glycol,
the worse the heat transfer. This causes local overheating which you will not necessarily see
on the temperature gauge. This is because glycol has a much lower thermal conductivity, specific heat,
and thus overall heat transfer coefficient than water. The figures in the table below are from the
BOSCH Automotive Handbook, and say it all. (I can't get the computer to close the gap!!) Some of the
better motor manufacturers will warn you of this heat transfer reduction in the Owner's Handbook.

- Despite decades of advertising jargon, glycol is NOT a summer coolant. It actually makes things worse.
Despite the combustion chambers being much hotter when glycol is added, the engine doesn't always boil
due to the effect of the increased boiling point caused by the glycol.

- Many old cars have marginal cooling systems, and get quite temperamental in hot weather. Draining all
the glycol out and replacing with water and AQUACLEAR often makes a huge difference. The reason is that
with glycol your engine metal parts and under bonnet temperatures are much higher. This encourages fuel
vaporisation both in the lines and in the carb. This can cause either fuel starvation, or over enrichment,
or both, depending where the vaporisation is occurring. The hotter petrol also gets thinner, which makes
it run through the jets much easier, thus making the mixture too rich. All this adds up to poor running
when the engine metal and/or engine bay is too hot.

- Cars in at least half the world do not require anti-freeze. Anti-freeze is a huge multi-million dollar
industry, and it has run a very effective brainwashing campaign over the past decades worldwide, and has
got the motor industry on board. In years past a few of the better car manufacturers used to specify
straight corrosion inhibitors when cars were destined for frost free regions.

- Anti-freeze is toxic to humans and animals, and is an environmental pollutant. In this country it is
almost never stored safely, or disposed of correctly.

- Spills of anti-freeze, even diluted, can severely damage paintwork, especially on older cars,
which are often ducoed or enamelled.

- Glycol mixtures use more engine power to pump around the cooling system than water due to glycol
being heavier and more viscous.

- The rules for an effective cooling system on an old car are as follows:

# Fit a heavy duty tropical core to the radiator.
# Fit a +-74degC thermostat.
# Control boiling, especially after engine shutdown, with a +- 50kPa (7 psi) radiator cap. You don't
want to go too high on an old car! This will increase the boiling point by approx. 12 degC.
# Ensure the thermostat has a bypass shut-off valve on the back if the engine design demands one.
# Restrict the bypass line with a 6mm orifice if there is no bypass valve in the engine design.
# Fit a suitably sized expansion bottle if the car does not have one. This dramatically improves cooling,
and reduces corrosion, by preventing air being constantly pulled into the water. A full top tank also evens
out tube flow, thus improving heat transfer to the air.
# Use no, or as little anti-freeze as possible for your conditions.
# Always use AQUACLEAR as per the instructions.
# Do not ever use soluble oil. It reduces heat transfer worse than glycol, and rots hoses
from the inside out.