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  #1  
Old 11-11-2005, 12:07 AM
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Default Anybody had problems with the viscous fan

I know a fellow that bought a new Mopar perf. viscous fan package and installed it on his 71 Charger 440 6 pack only to have it blow apart the first time he took it up to 5000 rpm. Took out the radiator and shroud and left it's mark in the hood real good. He sure wasn't very happy after 2 yrs. of restoration and boocoo bucks but thought it was just a defective part since he has had many Mopars in the past and not had any problems with this type of fan. Well they warrantied the first one. He put on another and in less that 1000 miles the same thing happened. After that he went with a flex fan and hasn't had any problems in 4 yrs.

Anybody else have any problem with them? Anyone running them? Anybody got a better suggestion for a fan?

I'm getting ready to assemble my Cuda and it came with a new viscous fan but I'm kinda leary after seeing this happen.

Thanks guys.
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  #2  
Old 11-11-2005, 11:43 AM
kamstra kamstra is offline
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I bought a new fan when I saw a picture of an older fan that had blow apart. Make sure all the bolts are tightened and it should be just fine.

Rob
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  #3  
Old 11-11-2005, 01:55 PM
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Never. I think I have about 10 years on it.
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  #4  
Old 11-11-2005, 05:23 PM
dodger1 dodger1 is offline
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I put a Hayden viscous fan hub in my 360 Mirada about 4 years ago to replace the old ('84 5th ave) unit that had gone dry (wouldn't hook up). Not one problem. What went - the viscous hub or the fan structure?
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Old 11-11-2005, 06:43 PM
George G. Leverette George G. Leverette is offline
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I buy the fans from the wrecking yards and the bettter grade clutches from the parts house. Never experienced any problems.
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  #6  
Old 11-11-2005, 08:32 PM
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I been using the mopar viscous fan for 5 years now with no problems. My stock unit was destroyed when, for the second time, a stock water pump blew at about 4500 rpms. First time no other damage but the second time the fan buried itself into my newly recored rad. I switched to a Milodon pump after that. As dodger1 asked what part exactly failed?
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Old 11-11-2005, 09:48 PM
B1owner B1owner is offline
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Yep, same here, no problems with mine either. about the only complaint I have about them is they doubled in price the last five years.
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Old 11-11-2005, 10:14 PM
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Back in my USAF days (>25 years ago), a friend of mine had a 68 Charger with the 383. He replaced his fan coupler at least twice in the 3 years we were on station together. But that was a long time ago, hopefully design and construction quality has improved. Personally, I've never had any trouble, except that the one on the Durango is terribly noisy. Has been since day 1.

And for what it's worth, be careful of those flex fans. They've been known to fly apart, too. I don't think I'd be standing in line with one if I had the hood up with the engine running at high RPM. Again, no personal experience, just what I've been told from some old hotrodders I converse with.
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Old 11-11-2005, 10:32 PM
Dart 65 Dart 65 is offline
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My '02 Durango has one and it makes a hell of a lot of racket. It's already been replaced once. The deisgn looks identical to the one I have from MP.
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Old 11-11-2005, 10:38 PM
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Quote:
Originally Posted by dodger1
What went - the viscous hub or the fan structure?
He said the fan structure split apart and lost a blade. He shut it down immediately so only one blade came off. But when he told me he had 2 come apart it got me to wondering. Might have just been a short lived bad run on fans and he was unlucky. The one that came on my car has about 500 miles on it when I took the engine out to rebuild it. I don't see any visible problems so since most haven't said they had any problems I'll stick with it.

DanL I have seen what can happen when one of those flex fans come apart too. I know a guy that don't have a left eye now from one. Lucky he's alive.

I'm sure it's possible for any fan to come apart.

Thanks for all the replies.
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  #11  
Old 11-11-2005, 10:48 PM
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Quote:
Originally Posted by Dart 65
My '02 Durango has one and it makes a hell of a lot of racket. It's already been replaced once. The deisgn looks identical to the one I have from MP.
OK. My 02 Dakota with the 4.7 has a clutch fan and I noticed it's pretty noisy too. The clutch is alot more hefty than the one on my Cuda though. It also has 7 blades instead of 5. The one on my Cuda looks like what I used to see in the 70's cars.
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Old 11-11-2005, 11:05 PM
Dart 65 Dart 65 is offline
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Yeah, we have basically the same vehicle. The fan is noisy when the truck is first driven after sitting overnight. The noise does go away after a few minutes, and it seems to be after it shifts into second gear.
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Old 11-11-2005, 11:59 PM
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Quote:
Originally Posted by Dart 65
Yeah, we have basically the same vehicle. The fan is noisy when the truck is first driven after sitting overnight. The noise does go away after a few minutes, and it seems to be after it shifts into second gear.
Yeah that's what I noticed too. I guess the oil settles at the bottom of the clutch and after a minute or so disperses and starts working properly.
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Old 11-12-2005, 12:34 AM
dodger1 dodger1 is offline
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What's interesting here is, it seems the fan itself was faulty, not the viscous hub, or coupler as someone referred to. Is it possible to compare the Mopar replacement combo to a stock 5 or 7 blade OEM unit? And if so - any obvious differences? Did your pal talk to Mopar Perf. about it? One thing I've heard is that the viscous hub fans, by design, won't exceed approximately 3500 RPM due to built-in slippage. Could that mean the fan structure isn't designed or balanced for a higher RPM? I can't see that, as the last cop car I saw (and bought for parts) had a solid coupler so would not have been limited. Not to demean your friends competence, but I'm leaning toward a possible improper installation. One thing I found, at least with the Hayden clutch, was that the bushing supplied with it was almost an interference fit with the pump shaft, and took some fiddling to install tight and straight. If one thought it was but it wasn't, I could see it loosening, wobbling, and ........??
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Old 11-12-2005, 01:48 AM
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Your right it does sound odd. As far as comparing them I can't because I don't know anyone right now that has an original one. He did call Mopar performance and of course they never heard of it happening. As far as it being incompetant installation I don't think that could be it. Both fans separated and broke where the fan bolts to the hub. I didn't see them but I think it comes pre assembled so he would have had to just bolt it to the water pump. He is just an aqquaintance, not a real close friend so I'm not defending him because of that but in his defense I wouldn't be affraid to let him work on my car and I don't trust it with any more people than I can count on one hand. He's an excellent mechanic restoring several Mopars to #1 show winning quality. It would surprise me if he did something to cause it.

After the posts here have indicated that this dosen't seem to be a problem I wonder if the factory didn't over torque the bolts and crack the fan. Maybe had some gung ho kid working for awhile that thought tighter is better. Just speculation.
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Old 11-12-2005, 04:03 PM
dodger1 dodger1 is offline
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Yeah, it certainly looks like Mopar just got a bad batch of fans - everything seems to point to that. As for overtorquing the fan-to-hub bolts, wouldn't they pull the threads out of the aluminum hub first? (I don't recall if there are steel inserts for the threads.)
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Old 11-12-2005, 05:05 PM
Dart 65 Dart 65 is offline
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Wait, there's no oil in a clutch fan, is there? It just looks like the silver center part which bolts to the water pump and the fan. I always thought it worked sort of like a clock spring, winding up with the engine's rotation.
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  #18  
Old 11-12-2005, 06:10 PM
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Quote:
Originally Posted by Dart 65
Wait, there's no oil in a clutch fan, is there? It just looks like the silver center part which bolts to the water pump and the fan. I always thought it worked sort of like a clock spring, winding up with the engine's rotation.
There are two types of fan clutches, thermal and non-thermal. Thermal clutches respond to underhood temps. When the engine is cold, the fan is disconnected; when too much heat is generated, the fan is allowed to cool the engine. A bi-metal thermostatic coil mounted at the front of the clutch senses the underhood temperature and operates the clutch accordingly.
Non-thermal clutches operate based on the shaft speed of the water pump. At low and idling speeds the clutch allows the fan blade to turn at almost a 1:1 ratio. At high speeds the silicone fluid contained in the clutch will lose its ability to transfer the energy from the shaft to the fan clutch body (and therefore the fan) and the fan is then allowed to almost free-wheel, removing its load from the engine.
Also the Mopar viscous fan does not come assembled and the clutch doesn't have steel threaded inserts. One possible reason for failure could be excessive vibration from a bent pulley.
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Old 11-12-2005, 09:15 PM
dodger1 dodger1 is offline
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max, thanks. Had a senior's moment there - couldn't remember the details. Tracy take a look at Haydens sitehttp://http://www.haydenauto.com/fce.htm Interesting point there - water pump shaft or bearing could cause failure??
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  #20  
Old 11-12-2005, 10:21 PM
Tarrbabe Tarrbabe is offline
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Default Not sure but........

You may have just answered a question for me. I have had a noise like a fan belt slipping for a while and can't find it. I think I just did. Thanks.
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  #21  
Old 11-12-2005, 10:49 PM
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Quote:
Originally Posted by dodger1
max, thanks. Had a senior's moment there - couldn't remember the details. Tracy take a look at Haydens sitewww.haydenauto.com/fce.htm Interesting point there - water pump shaft or bearing could cause failure??
Yep. Good stuff to know. Says almost exactly what Madmax said. I haven't seen him in several months but next time I see him I'll ask him if he had any problem with the water pump or pulley which might have caused it.
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