Electric or Flex fan

[Deerhunter30]

I posted another thread about having little clearance between the fan clutch and the radiator. If I cannot get adequate clearance I will go to a flex fan or electric fan. What are the pros and cons? How expensive is an electric fan? What is involved in installing one? I'm just trying to understand all my options.

 

[Bounty__Hunter]

If you get in water, a flex fan will really pull itself into your radiator.

There are no downsides to an electric as long as you can spare the amp pull on your current electrcal system.

I bought a parts-store reversible 16" fan for $60, but the bearings went out after a year or so. Get an OEM fan, many get the dual-speed unit from a Ford Taurus, it's a good fit. OEM will last a lot longer and will likely be cheaper.

Be sure to wire a switch into the switched power going to the relay for the fan, then you can turn the electric fan off for deep water or mud, or when you need to do anything around the engine.

 

[judge09]

I have gone with the flex fan over an electric fan on many different vehicles. It is real cheap and takes 5 mins to install. On the other hand Bounty makes a very good point on the water issue.

 

[Deerhunter30]

One concern with the electric fan is that at this point my alternator is just barely adequate in my opinion. With my AC and headlights on I am getting a little less that 13 volts at my guage. To me that means that I am just keeping up with the need and putting very little into the battery. I fear that if I draw a little more that the alternator will not keep up. I thought about the flex fan and water and that is a negative no doubt. The extra horse power from the electric fan would be good. Money is a factor right now. I just spend a little over $600 for the carb, air/fuel gauge, radiator, and all that goes with that and don't have much left to spend on her. I might go with a flex fan for the time being and then either modify my fan clutch, find a shorter fan clutch, or go electric.

 

[MudderChuck]

Most everybody I´ve seen with a flex fan has gotten into deep water or mud. The fan ends up looking like a wad of junk. And often tears up the radiator.
Something I noticed, I´ve a whole collection of fans an clutchs from pre 90´s Chev and Dodge. The bolt pattern is most always the same. But the fan for many Dodges has a reverse pitch or rotation.

 

[Joopin]

Anyone using Wheel Spacers?

I put a flex fan on my 67 mustang and it was so loud it drowned out the sound of my V8! And it wasn't a good loud either... that put a bad taste in my mouth when it comes to flex fans... but since a jeep engine doens't have much sound to them I guess it wouldn't matter. I do think the fins will get beat up pretty easy though, they are very thin. I say go with electric, it may be more expensive but it will take some drag off your engine which is a bonus.

 

[MudderChuck]

On my YJ, I spaced the radiator back about an inch, and mounted a fan in front of the radiator. Don´t know the CFM of the fan, but it had two speeds and sounded like a Jet fighter at high speed, really sang.

 

[Bounty__Hunter]

You could likely pick up an OEM fan and OEM alternator with more Amp output at a yard for under $100.

I'm looking at upgrading the NipponDenso 70A alternator in my '95 YJ with a 136A unit that will bolt right in, average price of those in a yard was about $45. That's almost double the output.

If you've got the older Delco style alternator they are easily rebuildable for higher output.

 

[Deerhunter30]

Bounty,

Tell me more about this alternator rebuild/replacement. Where do I get the rebuild kit? What model cars can I get a better donor alternator from? This might be a two step process....radiator and flex fan now......electric fan and alternator replace/rebuild later.

 

[BakedAlaskan]

I am with ya on what alternator for our CJ makes a good swap. I am going with the electric fan option myself. I already peeled open my radiator with my fan. No water needed.

Under 13 volts ain't good at all. You might need to replace your alternator anyways. Might at well upgrade before it leaves you stranded somewhere. Unless this is under full load then you might just be straining it.

 

[XJNick]

If it's the dash gauge that is reading under 13 volts, that probably isn't an accurate reading. Keep in mind that the volt meter is connected through a lot of small wiring thru many connectors before it reaches the battery. Voltage loss is inevitable. Even worse, most OEM gauges aren't very accurate.

Try placing a good voltmeter directly across the battery terminals and see if the voltage output of the alternator is around 14volts.

It's also probably worth checking and cleaning all the main power connections and especially the main ground connections.

-Nick :!:

 

[chinard]

Bounty,

Tell me more about this alternator rebuild/replacement. Where do I get the rebuild kit? What model cars can I get a better donor alternator from? This might be a two step process....radiator and flex fan now......electric fan and alternator replace/rebuild later.

Alternator rebuilds are usually pretty cheap, but if you want any kind of reliability, go with a brand new alternator.

The good news is that ANY STANDARD Mopar or Declo type alternator will work!
A couple of months ago i installed my 150 amp powermaster and its been awesome ever since.
For general usage i wouldnt install anything less than 100 amps even though the stock alternator is only 60amps.

One thing to keep in mind with alternators is the fact that most of them are rated at highway speeds for a normal modern day car which they consider to be about 6500 rpm. They consider 2500rpm to be idle speed.
Now those of you with 258's know that 2500 is highway speed and 600-700 is idle speed, so when sizing your alternator, you should pay closer attention to the rated idle speed (which for my 150a alternator is more like about 85amps)

 

[Bounty__Hunter]

www.jcw.com has hi-amp alternator rebuid kits, I did it to the Delco in my '88 YJ. Like was mentioned, you need to run higher rpms, 1500 and up, to benefit from the higher amperage.

 

[Bounty__Hunter]

Click HERE, all for under $50.