I was considering replacing the factory engine fan on my 4.0L explorer with a couple of electric ones mounted to the radiatior. First, before you call me crazy, let me ask a few questions. I have heard that an easy way to gain a few HP is to remove the engine mounted unit and replace it with a couple of eletric ones. Now, I know that the fan on the 4.0L is plastic and can't be draining too much off of the engine, but I was wondering if it may be worth it. Another reason I was considering this is that my Explorer has 132K mi. on it and the water pump is starting to show its age a little. Mid-summer days in columbia, SC are starting to get to it, and if I am at a light for any extended periond of time, I am entertained by the temp. needle inching up towards the H. Anyway, I guess my next question is, if I put two eletric fans on my radiatior (one push, one pull) of sizes not yet determined, and of course tieing it into the temp gauge, would it be bennificial? My position here is that if it is tied into the temp gauge it could displace more air at idle (stoplight conditions) than the stock engine fan. Once again, I am merely in the theory stage of this project, so any remarks, contributions, or objections are more than welcome.

Thanx,
Erik

 

Anything is possible if you want to take the time and hassle to try it, but I would recommend you fix your original problem.
To do an electric fan setup properly, you should put a sensor to cut the fan in and out as needed and possibly something to switch it into a high mode for extra cooling on those really hot days.

My high mileage explorer was having the same problem you mentioned on those special days in South Texas. I went thru all the checks and replaced thermostat, had rad cleaned, ect,ect and was still having problems.

Finally, I relpaced the fan clutch (and the cracked fan as well) and the problem was cured. Now I have that familiar fan roar when I first take off and things are cold. The clutch just was not tight enough anymore to keep sufficient air moving to cool on those really hot days.

Dialtone

 

You have the theory pretty correct, except for a couple things to be wary of:
1) Electric fans are not good when used on a vehicle meant for towing. If you do not tow, then the electric fan is the way to go.
Things to be concerned about when using electric fans only:
1) Amperage draw. You will kill your battery fast, if you do not put out enough amps to power your fan. 15 amps is about as much as your alternator will tolerate. If you do not use daytime running lights, or trailer lights, you can get away with a 20 amp fan, such as found on a Grand Marquis, or Town Car.
2) The electric fan is most efficient when used as a puller, not a pusher, i.e. mount it between the radiator and engine.
You will appreciate the electric fan making a more efficient use of heat transfer for your air conditioning on those hot Southern days.