Hey, Stuart, don't you mean LOWER the freezing point?!?
I don't know about adding any oil to the cooling system like that. It might be good for the pump, but what does it do to the rubber components? Most oils will attack rubber and soften and/or destroy it.
I'd stick with antifreeze, about a 50/50 mix, maybe with a bottle of Redlines Water Wetter or Royal Purples Purple Ice. I've used Water Wetter and it does work. And stay with the green stuff, Dex-Cool isn't compatible with the older pumps and the "non-toxic" stuff isn't as efficient.
