The dual fan setup has more square inches of opening for the fans, if pi r squared is the right equation. The single fan setup basically covers the center of the radiator and leaves a couple of 4-6 inch gaps on the sides, if you place it in the center, and the fan has very aggressively angled blades. At 50 miles per hour I'd have a chance of holding the mechanical fan and shroud outside my window with one hand. The single electric setup would break my wrist. Also, I was unable to get the top portion of my shroud to fit over the single fan setup, meaning that with the hood closed it was pulling some hot engine air over the radiator at idle. Nonetheless, the single fan setup brings temps down in a hurry when you are going slow or stopped.

What finally brought me to remove the fan was remembering the website FAQ and email I reported above, both stating that the single fan setup was the "improved" version and--seemingly unrelated--that the shroud should not cover the whole radiator to allow air to pass at higher speeds.

I was really irritated when I wrote that post, having spent a couple dozen hours changing and swapping things, gallons of antifreeze and distilled water, and boiling in the heat, and having spent a couple of hundred dollars on the fan. I'm sure those fans have their place... just not on my truck, at least not with the flat shroud.

My other issue with the electric fan was that it was on or off, so temps would rise and fall moreso than with the mechanical fan. Dusty's is wired to a water temperature sensor and probably more accurate. And, with higher temps on the highway due to my radiator, it was uselessly drawing current when it really needed to just get out of the way.

Bear in mind that I definitely need (and have ordered) a new radiator, so my temps will get better, but there is no doubt in my mind that the flat shroud and aggressive pitched single fan setup almost cost me another head gasket job.

It goes without saying that at 226 degrees my temperature gauge (dash) stayed right in the middle, lying to me like a guilty toddler.

If I had the dual fan setup I would gladly run the circuit and my guess is that I would get better temps than the "improved" single fan setup, but that I would get even better temps with no fan at all.

At the end of my post I almost jokingly posted to sell a barely used, improved fan setup, but I feel so strongly about this that I wouldn't even inflict that joke on a forum member. I tossed the fan in the trash this morning.

 

Charlie_v, I would purchase fan from you, just to try some variations, using stock shroud.

 

You can buy mine. Never used. Still in the damn box.

I would keep it and cut relief flaps, but I don't have the time for that.you want it, make a reasonable offer

 

I fished it off my trailer that was intended for the dump. Relief flaps is an interesting idea. Looking at it, the fan could, without a shroud, sit flat against the radiator but it would only cool at stop in the fan area... maybe half the radiator. With the shroud it is spaced about 3/4 of an inch from the radiator. I think flaps with the shroud would just draw hot air at stop, but help at speed.

I still hate the thing. I'm done with it. I'll cut flaps and try that out but it will have to blow my mind with low temps to make me trust it again.

 

I would tend to disagree. I'm looking at an electric fan shroud right now and it has cutouts. It's also a factory component so there is a little more engineering around this, but it has been done before and will be done again. Look around at the forums for builders. Lots of guys run relief flaps.

 

If it cools fine when it the fan is running, why not wire it to run continuously?

The only argument I've seen to switch it on and off is to save on wear and tear. I'd wire that **** to the accessories and be done with it.

Also, I guess i missed it - why wasn't the fan turning on at highway speeds?

Finally, I'd say the "it's either on or off" problem is a very valid concern, and a very good reason for a 2 fan setup where one runs continuously.

 

I'm with mordo, wire it to run all the time. That's what I'll be doing when I get a Ford Taurus fan with a controller to turn on the second speed since it's a 2 speed fan.

 

It is too bad you can't hook the fan up to a speed sensor and have it come on at say for grins, 10mph and below and shut off above that.

 

Well things have gone awry here... when temps rise it comes on no matter what your speed. The shroud is what is trapping hot air, so giving it a speed sensor or having it run all the time wouldn't help... mine was running all the time at speed... UNLESS the relief flap idea works.

 

This is what I have to work with.