Electric Fan Temperature Control Question

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May 26, 2010 | 12:37 PM

GreatNorthWoods

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From: Littleton, New Hampshire

Electric Fan Temperature Control Question

I'll be using an electric fan to cool the 302 in my 49 F-1. I am confused by the advertised automated on and off temperature control settings. I will be running a 180 degree thermostat and I'd like the fan to come on at about 190-195 degrees and go back off at around 185. I saw one temperature control advertised at "on at 190 and off at 170". Does that mean that once it comes on it would stay on at as long as the engine is running since I would have a 180 thermostat and the temp would never drop to 170? This is what I do not want. I want the fan to run only when the engine heats up to around 190 but go off when it gets back to operating temperature (180) or a little above. So, with that in mind what temperature control fitting would meet my needs best?

I also assume my fan may need a relay of some sort since it will probably draw 30-40 Amps or so. What exactly do I need there? I'm running a stock electric engine fan that came off a mid 80s V6 GM product. It probably ran continuously in its OEM setting but I do not want it to run continuously in my 49. It creates a lot of suction but it's pretty noisy. The radiator is a three row for a 390 Mustang so it should cool very well with only an occasional need for a fan.

Thanks for any comments or suggestions...

May 26, 2010 | 06:25 PM

Franklin2

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From: Virginia

Most OEM's run their fan on temparature pretty high, usually 220 or 230 degrees. They onyl run them all the time if the A/C compressor comes on.

What I used was an adjustable controller like this, autozone part number 733653. I also used 12v relays like this, Bosch Relays and Electrical Wiring Supplies

May 26, 2010 | 06:41 PM

GreatNorthWoods

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From: Littleton, New Hampshire

Quote:

Originally Posted by Franklin2

I drove the car this fan came out of. It did run continuously with the A/C, but with a 195 degree thermostat and no mechanical fan of any type it ran often even when the A/C was not on. Does the adjustable use a probe inside the radiator hose? I used one of those once years ago but never again...too hard to keep from leaking.

May 26, 2010 | 10:15 PM

Franklin2

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From: Virginia

Yes it does use the probe in the radiator hose, and yes it did leak. What I did was go to Lowe's and bought a 1/2" pipe tee, and two hose barb fittings. I screwed the hose barbs into the tee at a 90 degree angle, and cut my heater hose and spliced the tee in with hose clamps. I then bought a 1/4" brass compression fitting, and a adapter for it to fit the 1/2" tee. The probe just happens to be 1/4" od. I put all these fittings into the last 1/2" port in the tee, and slipped the probe inside the compression fitting and tightened it down. Works very well, and looks good also, with no leaks.