OK, the reason you have all the additives in your coolant is that some people think you need something to stop the water -- note that, WATER -- boiling in summer and freezing in winter. The cheap (and nasty) solution is ethylene glycol.
BUT, EG degrades with the extreme conditions in motors, to give corrosive byproducts. SO, you now need anticorrosion additives... Do a search on your fave engine for "ethylene glycol" to see the disaster. This is why you MUST change (preferably with a flush) your coolant AT LEAST every 12 months. Some older formulations need every 6 months.
One environmental result of this corrosion is the heavy metals washed out of the engine into the ground when you drain the radiator... This is also the reason you cannot drink the coolant when dying of thirst in the Simpson Desert...
The truth is that no place in Oz gets hot enough for well-maintained systems to overheat, and most places in Oz never get cold enough to freeze the system in less than 12 hours -- even in Canberra or Hobart. For snow-type winters, enclosed carports are more than sufficient to keep the cold out, or simply throw a blanket over the donk UNDER the hood when you get home.
OOPS! Nearly forgot: EG is basically an alcohol. If you have even the tiniest perforation in your heater matrix the EG vapour will intoxicate you as effectively as a shot of Jack Daniels. It will show up on the breathalyser just like a VB
, and in the BA sample like a bottle of plonk. Ever wondered about "single-car accidents" in the sticks at night? Now you know.
It is true that some water WILL cause corrosion in your head. Water ain't water. However, there are many good non-EG formulations around which can be added and will keep your system like new. In the past I have asked people to email me to get the name of one product made in Perth, but I'm getting lazy:
It is Flo-Kleen, available from Balcatta Radiators (08 9345 3122), 216 Balcatta Road, Balcatta 6021 WA. It costs about $30 for a bottle of 100 tablets, which should last for 24-30 months.
Disclaimer: I neither make nor sell the stuff. I use it, and I will never use EG again in any vehicle for any reason. Oh yes -- I use tap water.
Amniac -- if your system leaks, which it sounds like, don't bother with additives. Just use straight water, as it won't stay around long enough to do damage.