Jack,
Frankly, I don't think that it'll work very well at idle unless you are willing to see 300 F on the gage. For all the claims, it's got a considerably higher viscosity than water, with a lower heat capacity. The bottom line is that, at idle where it's the most critical, it won't carry as much engine heat to the radiator. The good part is that blowing air through a 300 F radiator is more efficient.
Using this stuff would be a desperation move for me.
Of course I could be wrong.
