I need the forum's input on manual engine cooling

[lsmalley]

Bought the resistors at radio shack for $1.40. I have the 1k ohm resistor, but what do the different ohm numbers mean? I.e., 5 ohm, 1m ohm, 100k ohm, etc. They had a lot to choose from. How do the xx ohm numbers correspond to the temp at which the high speed fans turn on? Thanks.