# Electric Cooling Fan and Thermostat Mod



## TheRepairMan (Jun 30, 2009)

I'm seriously thinking of doing an old street rod mod to my D21. I would like to get rid of the mechanical cooling fan and fan clutch. There are some advantages and disadvantages to doing this but I'll be the Guinea Pig here and document the work as it progresses. I'm putting together a list of parts I'll need, and my budget is to stay under $100 for everything.

Here's the fan I'm thinking about using. It's 16" X 3.5", RATED AT 2350 CFM, and draws 14 amps to start and 7-8 amps running. Lifetime warranty from a local company who's been in business for 40 yrs.









I guess my biggest fear is that the electric fan I install will either draw too much current for the stock battery and alternator to keep up with, or that the fan will not move as much air as the factory set up. What do you guys think?

-R


----------



## skramer360 (Aug 14, 2005)

I took one off an old Buick, fabbed up a shroud and slapped it on. Use a relay to get the fan motor going, otherwise you will melt wiring. I put the thermostatic switch in the upper radiator hose. I also wired in a switch in the cab, so I could turn it on in case the temp switch failed. I never needed the inside switch though. It worked fine, never had any power problems. Good luck with the mod.


----------



## Asleep (Jan 19, 2003)

im not seeing the big deal here. fans are not used while you are driving or moving. they are only used when you are stopped and are not getting air flowing thru the radiator. just make sure the polarity is correct and that you are pulling - if mounted engine side, or pushing, if you mount it bumper side. i have dual altima fans with an adjustable electric thermostat on my 400+hp sr20 and along with water wetter, i never get over 1/4 on my gauge.


----------



## TheRepairMan (Jun 30, 2009)

That's what I wanted to hear! Getting it installed with a temperature adjustable controller should only run me about $80.00 for both items, and a little bit of time to lay it all out under the hood.

I'm hoping to gain that all back in a very slight gas mileage increase that it could potentially make over a period of time. It may not amount to that much, but I know it takes some small amount of horsepower power to spin the mechanical fan all the time, and with an electric fan most likely nothing extra will be consumed while on the highway where air is forced through constantly. The only time the electric fan should come on and consume energy would be in stop and go traffic. Yeah, I know, normally the fan clutch takes care of this, but it's still not as efficient.

The main thing that had me looking into this is the extended warm up time during the Winter months. If you've ever noticed, on really cold mornings that fan clutch is pretty much fully locked up during the warm up period. That not only consumes more gas, it draws super frigid air through the radiator and over the engine when it's least needed. I go back to the truck after 15 minutes and it's still way below normal operating temps on a 30* or cooler morning. Forget it if it's near 0* ...it's still not warm when I get to work. 

The only thing I'll have to run into my controller extra is a means of triggering the controller when the AC is on. I think the controller has an extra signal wire that can run directly from the HOT wire at the Compressor Clutch. If that's so, then the fan would kick on when the AC compressor is called for, and go off with the clutch cycling off unless the temps call for it to run longer.

I'm hoping to keep the factory fan shroud and actually mount the fan just inside its funnel to utilize the entire shape of the shroud to pull air through the whole radiator, rather than having to mount the fan flat against the radiator which can over stress the tubes, and will also leave hot spots in areas of the core.

Here's a copy of the instructions for the controller I have used on other vehicles.









Looking more closely at the adjustable control relay, it's rated to carry a pair of 15 amp fans, 25 to 30 amps total, so it will handle the fan I'm going with just fine, and I'm thinking this isn't really as much electrical load on our trucks as I was concerned about earlier. I think normally there is so much more in reserve capacity that I may not notice when the fan comes on, other than the normal sound of air moving through the radiator.

Well anyway, that's my theory at this point, and I think this should work pretty well. I'm thinking about it too much ...bla, bla, bla. Let's just do it before Summer gets here!

-R


----------



## Asleep (Jan 19, 2003)

just remember that the fan has an optimal distance that it needs to be on the radiator. too much gap and it wont pull enough air over the fins. also, be sure to mount the temp tube as close to the upper hose inlet as possible. good luck with your project. i know i love it on my 240.


----------



## TheRepairMan (Jun 30, 2009)

Asleep said:


> just remember that the fan has an optimal distance that it needs to be on the radiator. too much gap and it wont pull enough air over the fins. also, be sure to mount the temp tube as close to the upper hose inlet as possible. good luck with your project. i know i love it on my 240.


The mech fan has a pretty big gap between it and the shroud. I was thinking if I can make the elec fan fit snugly to the funnel it would have to pull evenly through the rad. I'll even reseal the shroud to the edges of the radiator during the installation to be sure.

I'm glad you brought that up, though. I'll test it all out to fit to the most effective location. Right now I don't even know for sure if the 16" fan is my best option. I have yet to take exact measurements, but I'll report back as this comes together.

~R


----------



## Asleep (Jan 19, 2003)

The mechanical fan can afford to be that far away because of the shroud. Typically, people hook those electric fans up without a shroud, so that's why they recommend a distance for you. It's not much though and I think the little feet the fan come with actually take care of it for you.


----------



## TheRepairMan (Jun 30, 2009)

Asleep said:


> The mechanical fan can afford to be that far away because of the shroud. Typically, people hook those electric fans up without a shroud, so that's why they recommend a distance for you. It's not much though and I think the little feet the fan come with actually take care of it for you.


I agree. It makes for a cleaner installation without a shroud, especially in street rod applications. But, where I pretty much have all the room in the world, and don't care what it looks like, I'm going to attempt to keep the shroud in place with the new fan tucked away just inside.

I think all factory electric fans have some shroud, even though they aren't very deep. I'll know more about my set-up after mocking things up a bit. Even if I don't end up using the shroud, I'd rather not use the plactic pins sticking through the core to mount my fan. I'll make some brackets for it in either case to keep it from actually touching the core.

-R


----------



## Asleep (Jan 19, 2003)

yeah i didnt mean to sound like i was shooting your idea down. im sure when used in conjunction with the shroud, the fan should work quite well. you really will feel the difference in power too. removing the stock fan was the first thing i did to my s10 when i got it. made a huge difference.


----------



## TheRepairMan (Jun 30, 2009)

Asleep said:


> yeah i didn't mean to sound like i was shooting your idea down. I'm sure when used in conjunction with the shroud, the fan should work quite well. you really will feel the difference in power too. removing the stock fan was the first thing i did to my s10 when i got it. made a huge difference.


That's good to know!

I just measured the stock fan and shroud as best I could.

Looks like the stock fan, tip to tip is right at 16", and the opening in the shroud is about 18-3/4". So, it looks like the 16" fan they sell should fit pretty well. 

I imagine I'll have to take the shroud off and custom make four brackets to mount the fan in place. I've got all sorts of spare, pre-drilled channel bracing left over from a hardware kit that came with my TV wall mount kit that will be perfect for this.

FYI, here's a link to the fan... http://www.ebay.com/itm/SUPER-16-RE...Parts_Accessories&vxp=mtr&hash=item4cfd2e05ea

-R


----------



## Asleep (Jan 19, 2003)

i was gonna ask you if the fan you were going to use was reversible - that link answers my question. lol


----------



## TheRepairMan (Jun 30, 2009)

Asleep said:


> i was gonna ask you if the fan you were going to use was reversible - that link answers my question. lol


Yeah, I've done pusher fans before, but due to the space constraints, I'd have to do two very small fans, like two 8's or maybe 10's in front of the condenser coil. In my past experience that just doesn't seem to let nearly enough air move through the radiator as a large single, correctly installed puller can.

-R


----------



## Asleep (Jan 19, 2003)

funny thing, i tried to "upgrade" my fans on my altima by going from the dual 10's to a single 16"... yeah, that didnt go too well. the car hated it and it would overheat. made no sense. but i went back to the original fans and it was happy. weird.


----------



## TheRepairMan (Jun 30, 2009)

Asleep said:


> funny thing, i tried to "upgrade" my fans on my altima by going from the dual 10's to a single 16"... yeah, that didn't go too well. the car hated it and it would overheat. made no sense. but i went back to the original fans and it was happy. weird.


Now you're freaking me out! Maybe that was one of those "bad" 16" fans that Skip mentions in his sale description. hahahaha!

I realized when I found the fan in my first post that the company is actually located only 26 miles from me. I hope to run down there in a day or two and get a hands on look at whats needed to do this mod. I feel they will stand behind their products, and I won't have to mail stuff back and forth if I have a problem.

I'm also getting that little voice in my head that says I need to go ahead and do the timing chain kit while I'm in there. Yuk!

~R


----------



## Asleep (Jan 19, 2003)

lol, well, to be honest, about 10k miles or so later, the engine went. i think it might have been related to the engine not liking the fan. i think it had either a clogged radiator or a bad head gasket and the reduced air flow at idle or low speeds was probably not the best thing for an unshrouded electric fan. you know (food for thought coming up)... the single 16" fan is a good idea and im not saying you shouldnt do it, BUT, the altima dual fan setup worked better on my 240 than the single 16" did AND (and this is the good part, to me) they come encased in a fan shroud and for a couple bucks more, you can get the wiring harness from the same donor car you get the fans from... thats what i did for my 240. looks factory and works like factory. just food for thought.


----------



## TheRepairMan (Jun 30, 2009)

Well, I made a choice to go with the single 16" for several reasons, but it's on the way and I'll be picking up the adjustable fan controller tomorrow, so I'll keep you all posted on my progress.

-Roger


----------

