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1/19/2018 1:42 PM  #1


Flex fan or Clutch fan?

Guys at this time I have a flex fan and I"m looking at clutch fan as an option.  I have a 20" alum radiator with no cooling problems at this time.

What are you guys in Texas or living in hot places the use and why?  Just pros and cons

I know its hard to think about this now, Being winter and all

Last edited by mxjeffb (1/19/2018 1:43 PM)

 

1/19/2018 1:50 PM  #2


Re: Flex fan or Clutch fan?

I don't live in Texas, Jeff, but I have tested my heap on a drive to Las Vegas when it was 120 down there.  I have a 20" two-row rad with a seven blade thermal clutch fan and a good shroud.  The car normally never goes above the stat (195) and on that trip to Vegas with the AC going max it got up to around 210...maybe 220 sitting at a light.  I'm a believer in clutch fans and proper shrouds.

BB


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

1/19/2018 2:35 PM  #3


Re: Flex fan or Clutch fan?

Bullet Bob wrote:

I don't live in Texas, Jeff, but I have tested my heap on a drive to Las Vegas when it was 120 down there.  I have a 20" two-row rad with a seven blade thermal clutch fan and a good shroud.  The car normally never goes above the stat (195) and on that trip to Vegas with the AC going max it got up to around 210...maybe 220 sitting at a light.  I'm a believer in clutch fans and proper shrouds.

BB

Thanks Bob,
I see their are normal and heavy duty clutch,  normal spins 70% speed and HD spins 90% any thoughts on that and or what do you have?


 

     Thread Starter
 

1/19/2018 2:47 PM  #4


Re: Flex fan or Clutch fan?

Sorry, no idea.  Mine is a stock replacement for an 89 Lincoln Towncar.

BB


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

1/19/2018 3:57 PM  #5


Re: Flex fan or Clutch fan?

I live in deep south Mississippi, where it gets plenty hot and humid.  I'm running a clutch fan with shroud, stock 2-core brass radiator, and a/c.  I have no overheating problems.  I don't know what fan clutch I'm running.  I just know I bought it years ago from NPD.  There is a Thermal type fan clutch that will only engage the fan once it reaches a certain temperature and just free-spin the rest of the time.  If I ever have to replace my fan clutch I plan to try one of those.

Edit: Found an example of a thermal fan clutch... not very expensive either
http://www.jegs.com/i/Derale/259/22011/10002/-1?ymm=4294829711+4294829830+4294829436

Last edited by Michael H. (1/19/2018 4:01 PM)

 

1/19/2018 4:53 PM  #6


Re: Flex fan or Clutch fan?

Use a standard duty clutch...

 

1/19/2018 7:41 PM  #7


Re: Flex fan or Clutch fan?

I live in southeastern Virginia, summers are very hot and humid. I have a 66 coupe with a 289, stock size aluminum radiator, 6 blade rigid fan and NO SHROUD. I have no overheating problems. Even with the old brass radiator I never had a problem.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/19/2018 7:57 PM  #8


Re: Flex fan or Clutch fan?

X 2 on the standard duty fan clutch. The last heavy duty I bought didn’t stay. When it kicked in, the radio was drowned out by the airplane prop sound coming from under the hood.


John  -- 67 Mustang Coupe 390 5 speed
 

1/19/2018 10:47 PM  #9


Re: Flex fan or Clutch fan?

I live in the great state of Texas and I have had flex fans and fan clutches but the best thing I did was put in a wider aluminum radiator and a Ford Taurus two-speed electric fan. The Taurus fan has a built in fan shroud and moves plenty of air. I have read that it is more reliable than the after market electric fans. When I'm running about 35 miles an hour it turns off. Ive been real happy with it. Well it just a thought!


1965 Notchback, 8.8 rear end, T-5, Diy Front Struts, Shelby Drop, Bumpsteer Kit
 

1/21/2018 3:47 PM  #10


Re: Flex fan or Clutch fan?

A late 60's GM thermostatic clutch fan. Works great and it's quiet. Even without a shroud no problems.


I'm not a complete idiot.....pieces are missing. Tom
 

1/21/2018 9:24 PM  #11


Re: Flex fan or Clutch fan?

I used to have aflex fan but went to a fan clutch years ago.  Eventually i went to a spal  swirl blade electric fan. made a flat shroud out of some old speed limit signs, with a bunch of 2" holes with a holesaw. Painted it black to match fan. never had a problem living in bay area and later sacramento where it gets over mid 90's - 105 for a good stretch of the summer. a good water pump and a robertshaw/mr gasket thermostat and a good radiator cap make a big difference.  

 

1/23/2018 6:12 PM  #12


Re: Flex fan or Clutch fan?

Clutch fans cool well and reduce engine noise.  But, in my plan to reduce what can possibly go wrong the highest extent possible, I am running a 17" flex fan.

Either way, a proper fan shroud is mandatory. (stock 65/66 shroud does not qualify as a decent shroud)


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

1/24/2018 8:14 AM  #13


Re: Flex fan or Clutch fan?

I agree with the idea behind this, but I've never seen a mechanical fan clutch fail or known of anyone who had one fail.  I'm not saying it doesn't happen, but it's got to be rare.

 

1/24/2018 11:29 AM  #14


Re: Flex fan or Clutch fan?

Well thanks for all the input its all greats stuff,  I'm leaning to staying with the flex fan.
I have an over sized Aluminum radiator so cooling has not been a problem and if anything it has a hard time keeping heat.  I'm putting A/C on and I'm thinking more about the air through the condenser at idle if the clutch fan is not seeing to much heat it will not lock in (for lack of a better term) and spin the fan harder at Idle making good air flow over the A/C condenser when needed. I did a test with out the fan shroud (just because I had it off) with the flex fan and it pulls good air through the A/C condenser.  It will not only hold a paper on it will suck paper on from 3" away from the condenser.  I will do the same test with a clutch fan to see if it still pull good air at an Idle. I can live with any of the draw backs of a flex fan if it will help keep my A/C working better in the summer.
 

     Thread Starter
 

1/24/2018 11:30 AM  #15


Re: Flex fan or Clutch fan?

Michael H. wrote:

I agree with the idea behind this, but I've never seen a mechanical fan clutch fail or known of anyone who had one fail.  I'm not saying it doesn't happen, but it's got to be rare.

Just to keep the record straight, Michael, I did have a fan clutch fail (didn't come apart, just leaked out all the silicone grease) on my '69 Toyota Crown with 100+ K miles in about 1974.

BB


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

1/24/2018 12:56 PM  #16


Re: Flex fan or Clutch fan?

Bullet Bob wrote:

Michael H. wrote:

I agree with the idea behind this, but I've never seen a mechanical fan clutch fail or known of anyone who had one fail.  I'm not saying it doesn't happen, but it's got to be rare.

Just to keep the record straight, Michael, I did have a fan clutch fail (didn't come apart, just leaked out all the silicone grease) on my '69 Toyota Crown with 100+ K miles in about 1974.

BB

Interesting... what was the result?... noise?...vibration?...overheating?

 

1/24/2018 10:34 PM  #17


Re: Flex fan or Clutch fan?

I worked as a service manager for 9 years at a shop and saw plenty of them fail by locking up, vibrating, making noise, free wheeling, and coming apart, flying into the radiator. Sometimes you can check them by wiggling them and looking for leakage. Run your engine and you can hear it engage and dis-engage similar to an electric fan.


70, ragtop 351W/416 stroker Edel Performer heads w pro flow 4, Comp roller 35-421-8. T5
 

1/25/2018 3:42 AM  #18


Re: Flex fan or Clutch fan?

During your years as a service manager, how many flex fans did you see fail?  (Currently I have a flex fan and I've read on other threads that some folks don't trust them.)


1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
 

1/25/2018 11:15 AM  #19


Re: Flex fan or Clutch fan?

Far less than the clutches. But I don't remember seeing a whole lot of them either. The fans I remember were plastic or aluminum after market. One had loose rivets and the blades were rattling on the hub. Usually they were caught while servicing the car, cracked but hadn't let go yet. That was my job to let them know. For liability purposes we put the stock fan back on. The owner and techs didn't trust them either. A good flex fan looks almost like a regular fan made out of steel.


70, ragtop 351W/416 stroker Edel Performer heads w pro flow 4, Comp roller 35-421-8. T5
 

1/25/2018 2:25 PM  #20


Re: Flex fan or Clutch fan?

I did a search on Summit Racing for flex fans and saw they have them now made out of one piece nylon.  What does everyone think about these?  I don't see how these could fail.


1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
 

1/25/2018 5:40 PM  #21


Re: Flex fan or Clutch fan?

I got mine out of a junk yard and cut it to fit.  1970 351w.  There might be some of them still out there in an old junk yard.

  It just barely clears the radiator hose.  It has worked for me since 1989.  No balance problems and, more importantly, no heating problems with the Shelby front valence.


Original owner - 351w,T-5, 4whl disks, power R&P
 

1/25/2018 7:02 PM  #22


Re: Flex fan or Clutch fan?

WOW!!!!........don't go "brain-numb" while working on stuff and get your fangerz too close!......No room for errorrrrrr.
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

1/25/2018 9:25 PM  #23


Re: Flex fan or Clutch fan?

lowercasesteve wrote:

I got mine out of a junk yard and cut it to fit.  1970 351w.  There might be some of them still out there in an old junk yard.

  It just barely clears the radiator hose.  It has worked for me since 1989.  No balance problems and, more importantly, no heating problems with the Shelby front valence.

I had a 72 Gran Torino with one of those fans, one of the blades broke off and put a nice dent in the hood.

I still have it, but its grown into the crotch of the tree I put it in 35 years ago.


 


67 Coupe, 5.0 EEC IV Fuel injected. T5, 3:70 rear
 

1/26/2018 7:23 PM  #24


Re: Flex fan or Clutch fan?

red351 wrote:

I had heard that some time ago ford did a recall on their  flex fans. Still seems to be a lot of them out there yet. They look good hanging up in the archives and that's where mine will stay.

OR a crotch!!!!!
6s6
 


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

1/27/2018 8:49 PM  #25


Re: Flex fan or Clutch fan?

The 65 cars (maybe others) w/ AC had a 18" five bladed clutch fan.  It's nicely made with aluminum blades riveted onto steel fingers/hub.  You can still find them on ebay occasionally.


Cheap, Fast, Good:  Pick Any Two
 

Board footera


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