Elec. cooling fan mod.

[JKmotorsports]

Well, I just installed some electric cooling fans on my Tahoe over the weekend in place of the stock engine driven fan. Wow, what a difference. My A/C is much colder, especially at idle. Throttle response is a bit better as well as gas mileage. The stock fan puts such a parasitic drag on the engine.
I used two 16" 2500cfm fans with an adjustable thermostatic fan control so that it comes on around 180*. I wired each fan individually with its own relay and power source. That way if one fuse blows or a fan quits working, then the other will still continue running to help keep the engine cool. I also used another relay to switch the fans on when the a/c is on.
The trucks should have come from GM this way. I'll post some pics later.

 

[RonH]

Where did you get the electric fans and switches? Are they a stock item somewhere?

 

[JKmotorsports]

The fans I used are aftermarket from Proform. But the later model GM trucks started using electric fans as well. I couldn't find any complete GM fan setups, so I bought these for $75 on Ebay. The adj fan control was just under $20 from Autozone, and all the relays/wiring I just had laying around in stock. I have seen from two different sources some dyno numbers from the fan mod specifically on a 5.3 Tahoe. Both companies reported 10-12% increase in mileage, and one reported 17 more hp and the other 15 more hp. I knew the mod was a good one just from previous vehicles I've done this to, but I thought these numbers were a bit exagerrated. But after the mod on the Tahoe, I did notice a decent mileage increase and better throttle response; more than I expected, especially with a/c performance.

 

[JKmotorsports]

Wow! When I used to remote start my truck, it would take a while (about 5 mins or so) before the a/c would get cold enough and cool the truck down to a comfortable level.
Well, I timed it with my new fans, and now it's only a matter of a couple mins and it's COLD, even when it's over 100* out here.

 

[RonH]

I think it would be a good mod. I had a Cadillac Fleetwood Brougham with essentially the same 5.7L engine and 4L60E transmission that's in my 98 Suburban. The Caddy had electric fans. I was getting 20 or 21 mpg with it. I'm not unhappy with the Suburban A/C as it is, but it could be better in really hot weather. With both front and rear units turned up, it moves a lot of air and cools down pretty fast.

 

[yUkOn4uS]

IM YOUR BELOW AVERAGE DIY'r and i was wondering how this is done? do you mind giving me directions? my ac sucks cause im in traffic so much and it doesnt even stay cool at all.... i have van 03 y8ukon slt w/autoride

The fans I used are aftermarket from Proform. But the later model GM trucks started using electric fans as well. I couldn't find any complete GM fan setups, so I bought these for $75 on Ebay. The adj fan control was just under $20 from Autozone, and all the relays/wiring I just had laying around in stock. I have seen from two different sources some dyno numbers from the fan mod specifically on a 5.3 Tahoe. Both companies reported 10-12% increase in mileage, and one reported 17 more hp and the other 15 more hp. I knew the mod was a good one just from previous vehicles I've done this to, but I thought these numbers were a bit exagerrated. But after the mod on the Tahoe, I did notice a decent mileage increase and better throttle response; more than I expected, especially with a/c performance.

 

[JKmotorsports]

IM YOUR BELOW AVERAGE DIY'r and i was wondering how this is done? do you mind giving me directions? my ac sucks cause im in traffic so much and it doesnt even stay cool at all.... i have van 03 y8ukon slt w/autoride

You have to have a special tool to remove the fan clutch. I made one because the local auto parts store didn't have one for rent.
I'll send you a PM.

 

[Whipple1]

Well, I just installed some electric cooling fans on my Tahoe over the weekend in place of the stock engine driven fan. Wow, what a difference. My A/C is much colder, especially at idle. Throttle response is a bit better as well as gas mileage. The stock fan puts such a parasitic drag on the engine.
I used two 16" 2500cfm fans with an adjustable thermostatic fan control so that it comes on around 180*. I wired each fan individually with its own relay and power source. That way if one fuse blows or a fan quits working, then the other will still continue running to help keep the engine cool. I also used another relay to switch the fans on when the a/c is on.
The trucks should have come from GM this way. I'll post some pics later.

Hey JK that is a great mod,I also want to do this because I have the blower I added even more parasitic drag,Flex-a-lite makes one for our trucks it replaces the fan and the shroud with relays and controllable themostat.How loud is it in the cab I would like to see some pics,my a/c needs help also thats a couple of birds with one stone.Nice job!

 

[JKmotorsports]

Hey JK that is a great mod,I also want to do this because I have the blower I added even more parasitic drag,Flex-a-lite makes one for our trucks it replaces the fan and the shroud with relays and controllable themostat.How loud is it in the cab I would like to see some pics,my a/c needs help also thats a couple of birds with one stone.Nice job!

Thnx bro. It really isn't even noticeable in the truck. Not sure how much more audible it would be with stock exhaust though Haven't had a chance to take any pics, but will soon.

 

[Crazydefense32]

Does it increase towing power or ease towing at all? The ones I have looked at say that they are primarily good for towing purposes. Any info on that?? :Chevy:

 

[JKmotorsports]

Does it increase towing power or ease towing at all? The ones I have looked at say that they are primarily good for towing purposes. Any info on that?? :Chevy:

With the fans running full speed when they are on rather than varying with engine speeds, and the fact that they pull more air through the radiator/coolers, I'm sure it would help to keep tranny temps down a bit as well, especially with a tranny cooler. Overall cooling efficiency of both engine and tranny is increased over an engine driven fan. And without the added parasitic drag on the engine, you reduce a degree of strain on the engine, gaining some hp and torque.

 

[Armycop]

I'm an above-average DIY'er, could you send me your parts list and write-up as well? Thanks!

 

[JKmotorsports]

I'm an above-average DIY'er, could you send me your parts list and write-up as well? Thanks!

When I get a chance, I will put together a parts list and some tips and post for eveyone interested.

 

[Crazydefense32]

Thanks for the info!! :Chevy:

 

[Coastie Kyle]

Also interested......

 

[JKmotorsports]

I have been asked by a few people for a parts list and instructions. I opted to put together my own kit, purchasing universal items here and there. Most of the wiring, relays, etc were stuff I have laying around the shop. It may be easier to purchase a complete kit from sources such as Summit Racing and Jegs, for they have everything you need with much more detailed instructions than I would be able to provide. I have, however, provided a list of parts I used and the removal procedure for the factory fan, shroud, fan clutch,etc.
For installation of your new electric fans, follow the guidelines with your new assembly. If your kit does not come with instructions, such as with some universal kits, feel free to PM me with the type of kit you purchased and I will help as much as I can. As for wiring, some kits will come with the required wiring, relays, instructions, etc., but like above, you may PM with any questions. It's been raining like crazy here and I've been so busy with work that I haven't been able to take any decent pictures, but will when I get a chance.
Here's a list of what I used:
Two(2) 16" Proform electric fans, S-curve type blades(quieter than straight blade design), 2500cfm each, w/mounting kit.
Three(3) SPDT relays, 30/40A. One for each fan, one to operate fans when a/c clutch is engaged.
One(1) adjustable electric fan control thermostat
One(1) 3A diode, to prevent feedback current to a/c clutch circuit
Two(2) ATC type fuseholders with 30A fuses
Misc related 12 ga. wire, solder, heatshrink,etc.

Following is the procedure for removing the fan shroud and fan blade/clutch assembly. This is for the 4.8 and 5.3L engines. The 6.0L procedure is almost identical, with the only difference being in the lower fan shroud removal. When I get a chance, I will post some detailed pics for the procedures below, pointing out locations and such.

Special Tools Required
J 41240 Fan Clutch Remover and Installer
J 41240-5A Fan Clutch Wrench


Fan Shroud Removal-Upper
Loosen the air cleaner outlet duct clamps at the following locations:
Throttle body
MAF/IAT sensor
Remove the radiator inlet hose clip from the outlet duct.
Remove the air cleaner outlet duct.
Reposition the inlet hose clamp at the radiator.
Remove the inlet hose rosebud clips from the following locations:
Fan shroud
Air cleaner outlet duct
Remove the inlet hose from the radiator.
Reposition the radiator inlet hose.
Remove the fan shroud retainers.
Remove the fan shroud bolts
Remove the upper fan shroud.

Removal Procedure for fan blade/clutch assembly
Install the J 41240 to the fan clutch. Using the J 41240-5A Fan Clutch Wrench on the hex shaft of the fan, loosen the fan clutch assembly.
Remove the fan blade.

After removing the fan, you can remove the lower fan shroud assembly.
The 6.0L will have a couple oil cooler lines attached to it which will need to be removed.

Hope this is helpful.

 

[JKmotorsports]

Here are some pics of the install. When I get a chance, I will take some detailed pics for the above instructions.

 

[JKmotorsports]

Flex-a-Lite fans from Summit Racing

Perma cool fans from Jegs

Proform GM electric fans

 

[JKmotorsports]

Just calculated mpg with fan mod

Well, seems like the fan mod added another 1mpg avg over the last 3 tanks.
MPG went down with the wheels to 12.5 mpg. Now, together with the exhaust, intake, and the elec fan mods I'm back up to 15mpg.

 

[STREETutilityVEHICLE]

good thread, i'm going to be doing this as well in about 2 weeks. i'm also getting the S&B intake, is that what your running? if so how do you like it? again, thanks for the info!