Suitable coolant / Corrosion inhibitor.

[Lynn Eades]

Hi Guys,
What are the current mainstream thoughts on inhibitor?
Glycol ethylene used to be the only option. Now we have Water wetter, green coolant, red coolant, and unknown numbers of various additives.
I have had my recond. carrier motor running for about 6 months with just plain water in the system. It does not leak, but I need to put some kind of corrosion inhibitor in the system. I have alluminium heads fitted, composite head gaskets, torqued to 35 ft lbs (once) and standard water pump seals.
The antifreeze is unlikely to be required with only the odd light frost in winter.
I don't need any info on the likes of soluble oil.
What's the advice?