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Old 12-20-2012, 12:51 AM   #1
heathbirkendahl
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Clutch fan or flex fan?

Is it worth running a flex fan vs. a clutch fan?
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Old 12-20-2012, 01:22 AM   #2
Andy4639
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Wink Re: Clutch fan or flex fan?

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Originally Posted by heathbirkendahl View Post
Is it worth running a flex fan vs. a clutch fan?
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If the truck has AC don't even consider it, if not it may be OK. I haven't had much luck with the flex blades though.
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Old 12-20-2012, 01:34 AM   #3
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Re: Clutch fan or flex fan?

BEEN ON MINE SINCE DAY 1.But been wondering about a flex fan I think it would be quieter.
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Old 12-20-2012, 01:44 AM   #4
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Re: Clutch fan or flex fan?

In the 35 years I've owned my truck the only time it ever ran hot was when I temporarily had a flex fan on it. No problems ever with a clutch fan. Mine is OEM with an 18" seven-blade fan (factory A/C). I will never recommend a flex fan.
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Old 12-20-2012, 01:57 AM   #5
heathbirkendahl
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Re: Clutch fan or flex fan?

No A/C and it sounds like I need to forget the flex fan idea. Electric fans with the 4 core it is.
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Old 12-20-2012, 02:25 AM   #6
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Re: Clutch fan or flex fan?

I would keep the clutch fan on if you still use your truck in hauling stuff and towing up steep grades ,and on long trips. A flex fan is good for around town drives and if you don't use your A/C a lot during hot weather conditions. I have a Perma Cool flex fan and I wish I would of got a new clutch fan.
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Old 12-20-2012, 02:39 AM   #7
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Re: Clutch fan or flex fan?

Been wondering about that. Mine doesn't have ac.
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Old 12-20-2012, 02:46 AM   #8
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Re: Clutch fan or flex fan?

When my truck ran hot with a flex fan (posted above) I wasn't running the A/C.... but I was hauling a load of firewood uphill. Might have been OK if I just drove around but not when gets worked like a truck, which mine still does.
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Old 12-20-2012, 02:56 AM   #9
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Re: Clutch fan or flex fan?

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BEEN ON MINE SINCE DAY 1.But been wondering about a flex fan I think it would be quieter.
flex fan quieter? lol

nope, abuot a billion times louder than a clutch fan.
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Old 12-20-2012, 07:28 AM   #10
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Re: Clutch fan or flex fan?

Every so often I like to post these pictures of my truck that HAD a flex fan on it. It was on the truck when I bought it and I will never use one again for obvious reasons!

Note, the strange looking hood ornament! (could have been my skull!)

BTW, that didn't just go through the flat sheetmetal but half way through the support under it!
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Old 12-20-2012, 08:23 AM   #11
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Re: Clutch fan or flex fan?

I ditched my flex for a factory type clutch fan , im not much on electric just more stuff to fail
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Old 12-20-2012, 08:32 AM   #12
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Re: Clutch fan or flex fan?

I have a flex fan now and will be switching to a fan clutch real soon.
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Old 12-20-2012, 09:01 AM   #13
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Re: Clutch fan or flex fan?

Reasons NOT to have a flex fan:

1. See photo above from bobs409
2. They are very noisy while on the gas.
3. You need kevlar gloves and sleeves to work around them. Very sharp.
4. They rob horsepower.
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Old 12-20-2012, 09:19 AM   #14
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Re: Clutch fan or flex fan?

The very first thing I did to my convertible when I bought it in 1989 is take that noisy, POS flex fan off that the PO put on. It made no sense to me then. After seeing that fan stuck through that hood, it makes even less sense. You could be working on it when a blade comes off. That could be your head!
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Old 12-20-2012, 09:34 AM   #15
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Re: Clutch fan or flex fan?

My truck had the stock steel fan on it and it was very loud so I switched it over to a 18" clutch fan and it is so much better now and the flex fans are still noisy at low rpms.
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Old 12-20-2012, 02:22 PM   #16
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Re: Clutch fan or flex fan?

Car Craft Magazine article, May 2000, page 50 and 51

Dyno test on fans:
alternator, no fan=496 HP
plastic flex fan=460 HP
low profile flex fan=466 HP
High-performance flex fan=476 HP
Rigid steel 6-blade fan=449 HP
Rigid steel 4-blade fan=473 HP
Thermal clutch fan=487 HP
non-Thermal clutch fan=485 HP
HD Thermal clutch fan=476 HP
alternator, electric fan (Black Magic 150)=494 HP

So, stay away from any rigid fans and flex fans. On their engine the clutch fan only used about 10 HP as opposed to 30 for a flex fan. The electric fan only used 2 HP!
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Old 12-20-2012, 02:30 PM   #17
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Re: Clutch fan or flex fan?

I wonder about the reliability. I have had thermal clutch fans fail and had to take them off and bang them with a hammer to lock up just to get home. I did also have a fiberglass flex fan come apart, while I was at idle thank goodness. It only banged out through the bottom.
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Old 12-20-2012, 02:42 PM   #18
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Re: Clutch fan or flex fan?

rigid style fans and flex fans do come apart and do use more gas.and are very noisy . i always try and go with fan clutch fans....that is not the first hood with a fan sticking through it that i have seen....ask ford motor company back in the 1970's....they have stacks of broken fans...
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Old 12-20-2012, 07:10 PM   #19
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Re: Clutch fan or flex fan?

I had a fan sticking through my hood and it was a clutch fan. Now I run an electric one....problem solved!
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Old 12-22-2012, 03:20 PM   #20
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Re: Clutch fan or flex fan?

Tossed out my flex fan and got a clutch and clutch fan from summit. 18" flx-5718 and hda 2705 .. Love it, simple to install... your real question should be, thermal or non thermal clutch fan? Hope i dont insight a riot!! good luck!
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Old 12-22-2012, 05:31 PM   #21
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Re: Clutch fan or flex fan?

^^ Thermal, of course!
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Old 12-22-2012, 08:29 PM   #22
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Re: Clutch fan or flex fan?

take those POS flex fans off ASAP just sayin' never did like them any fan blade really ,
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Old 12-22-2012, 08:45 PM   #23
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Re: Clutch fan or flex fan?

Quote:
Originally Posted by bobs409 View Post
Every so often I like to post these pictures of my truck that HAD a flex fan on it. It was on the truck when I bought it and I will never use one again for obvious reasons!

Note, the strange looking hood ornament! (could have been my skull!)

BTW, that didn't just go through the flat sheetmetal but half way through the support under it!
That pic is worth a couple thousand words.....think about standing over that engine (tuning)? Buzz the throttle a couple times (like we all do)....the hood was cheap to replace? That blade stuck in your head, would not be so good crazyL
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Old 12-23-2012, 09:17 AM   #24
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Re: Clutch fan or flex fan?

i think about this now alot (older and smarter) all that moving stuff could mess you up i've heard of the piece behind of the alternator pulley breaking and messing a guy up. i've had my hand smacked by a fan and thank God it wasn't a flex fan still numb for a couple hours.
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