thesals, There has been kind of an epidemic of fan questions lately. I hacked this out of a recent response for you. Some of the flex fan stuff doesn't pertain but take a look.

If you are seriously considering dumping a properly working clutch fan for electric you should note the several drawbacks. Besides the cost alone which could go towards something else or heck, even gasoline

Personally... I hate flex fans. They are only rpm controlled. This means they have no idea what the engine is doin workwise.

Examples:

Low gear hill climb: High rpm, hard work, lots of heat, flat fan = no air.

Long gradual freeway downhill: Low rpm, no heat, maximum fan = why?

Both electric and clutch fans deal with these types of situations because they are temperature controlled as fans should be.

Electric fans have a few drawbacks. They use a hell of a lot of electricity! 20 to 30 amps is not unusual. This is not a minor increase in a vehicles electrical budget. Often it requires eventual electrical system modifications. You may soon discover any electrical system shortcomings. They often mount with strange radiator modifications, hanging the fans on things plunging into the very radiator cores. This creeps me out in the age of $700 radiators. On the upside they cool a lot at idle if needed, (helps the A/C). They can cut all fan related energy consumption at freeway speeds and in cold weather.

Clutches: They can allow a very large fan load if desired but shut down when not used. As mentioned they can fail in nasty subtle ways. They are a heavy item to rotate quickly.

If you want maximum reliability a solid fan is it. Big loud!

Next would be a clutch which drops the noise level and increases the gas mileage.

Electric when engine mods or other things preclude other methods.

Fiberglass... Sim pel, cheep.


Another view on electric fans:

At 40amps worth of electric fans at 12 volts..

40A X 12V = 480Watts

480Watt/750Watts/HP = 0.64HP This is a little more than 1/2 a horsepower of air moving ability....

An engine driven fan can easily hit 5HP even up to 10HP.

This will move a HECK of a lot more air than any 12V electric fan could ever hope to dream of imagining of etc.

Now is this amount of air always required? Of course not! But when I'm on the way to the beach over the "hill" with a car load of stuff and people on a hot day, with the A/C on I fore-shore want to be able to tap that 5 HP if I need to.

The other thing that is not pointed out is... If the engine runs the fan runs... With electrics.. If the fuze blows the fans don't run. If the wiring fails the fans don't run. If the temp switch fails(I've had three fail) the fans don't run. If the relay fails the fans don't run. If the alternator has a problem you aren't going to get very far on total-loss while sucking 40amps.

These are the reasons you don't see electric fans on commercial vehicles. They aren't as reliable.. they can't be.


As for you over heating problem it might just be the fan's clutch.
Check this thread.

http://www.clubhotrod.com/forums/sho...threadid=12732