Need some advice

[chuzie]

Can't really run a temp through the aluminum radiator without the risks previously discussed during the cooling problem. Conversely, if you use a manual ON switch, you run the risk of forgetting to turn the fan on and don't realize it until you are too hot (like i do all the time).

Solutions:

1. Run a bright LED (or other light) somewhere in the typical field of view in the cab / dash to indicate when the fan is off. You could even make it blink or put a little buzzer or chime on it as a reminder to turn the fan on.

or

2. Run a standard external temp switch where it will not come in contact with the radiator but still receive enough heat to actuate. If you do this try to find a temp switch that has a lower threshold for actuation since the temp it receives will naturally be lower considering it is not in direct contact with the hot part of the radiator tubes.

Or

3. Run the fan to be hot off the ignition and place a switch in -line to manually turn the fan OFF when necessary (during engine run). Consider implementing solution 1 into this as well. No reason to really have the fan running when the engine is off since no water will be moving through the radiator. A constant ON switch is really obsolete versus a hot wired ignition setup.

or

4. They do have temp switches to place in-line with the actual water line ports on the block. Something similar to this http://www.prchotrod.com/products/cooling_accessories
I would definitely recommend this option though.