From Work Safe BC - a caution on flex fans - worth reading http://www2.worksafebc.com/i/posters/2002/wsflexfans.htm
I'd sooner have a clutch fan that does the same basic thing for air flow, but does not suffer metal fatigue the same way. Flex-fans have always been on my 'no-go' list.
I got news for them those will go right thru the hood too and the celing! Ford fans in the 70's or so did this same thing.
The 70's GM pick-up trucks had danger-fans too. I've never been a big "fan" of those aftermarket fans either. My GTO has a factory Pontiac flex fan that they used for HD applications and on Ram-Air engine cars and I've never heard of one of those having any problems, they even reproduce them. Have to keep an eye on it in any case. My car will run hot and the gauge will climb sitting in traffic with a clutch fan. It had one before I modifed the engine and afterwards I had to go with the flex. Runs cool all the time now, you wouldn't think it would make that much difference but it does. I tried several fan clutches thinking that was the problem too BTW.
Aluminum work hardens so this makes sense. So sad for the poor guy struck by the fan. Also be wary of aged plastic engine driven fans as the plastic can become brittle with age and disintegrate when asked to rev high. Fans are cheap, radiators, shrouds, belt driven accessories and hoods are not. Even though I know better I recently learned the plastic fan lesson the hard way. No injury to my person, just my wallet.
The one on my 78 t-bird let loose while I was working on it. Hit me in the side of the head. Luckily, it was winter and I had a stocking hat and hooded sweatshirt that cushioned the blow. The car was only 2 years old when it happened.
I stopped using aluminum flex fans and plastic fans years ago when I found them cracked and the plastic fans brittle and pieces missing. Actually we switched to plastic electric fans within shrouds. Altho plastic we haven't had any problems----yet!
Wow...thanks for the info Safari57. Sad to hear about that death. I have a flex fan on my car, and have always used them. They say that you loose hp and gain a lot of noise by switching over. I can't tell the difference in hp. "Seat of the pants" hp told me that I GAINED hp, and while driving, I don't even hear it. It DOES pull some air at idle though, which was what I was looking for. When I took my car to the dream cruise, while running the clutch fan, it got a little too hot for my tastes, so I had to pull over(do you know how hard that was!)to let it cool. Haven't had that problem sense switching over. Knowing what I know now, I'm going to buy a new one. They cost under $50 and seem like a good idea to replace during major tune-ups, which I plan to do. Thanks again for the info.
Hfab5 maybe that's a good idea. Use a fresh flex fan now and then. I did use them for years and only noticed stress cracks on the older cheaper ones. A good multiblade clutch fan with a GOOD cutch seems to work well if everything else is working correct in the cooling system. The shroud is very important.
flex fans are junk. their design seems to have little to do with actually cooling....pull more air when idleing, flatten out when the motor is working hardest? WTF? power robbing, noisey, inefficient, dangerous.
Friend had one on his 62 'swiss cheese' Catalina - took out the fan shroud and hood at 3000RPM! Expensive lesson!
Yeah, I've heard the good and bad about flex fans, but I will tell you that ANY fan flex, fixed, or clutch fans, will break from abuse. It can come from the mounts, bolts, or fans themselves. I've heard of it, just never heard of any injuries from it. Flex fans have come a long way in the past 5-10 years and most "now" are made with stainless blades, not the aluminium like they ALL use to be made from. If it didn't work for me, I wouldn't use it, but it keeps my 390 MUCH cooler than the "new" stock fan that it replaced. Thats what I was looking for, something to keep my car running cool at idle to low speed stop and go cruising. I believe that if you car/truck is running hot during express-way or extended mid range rpm driving, your problem may be a little deeper than a fan. Just my opinion and my experience.
So far, touch wood, I have never had a problem with an engine running hot in any weather, with the factory clutch fan doing its job properly. That includes 100 degree weather on the Beltway in Washington D.C. rush hour, doing 10 miles an hour for about 2 hours. The temperature gauge never moved out of the cool area. Of course, those Thunderbirds seem to run at the cool end of the gauge no matter what, if everything is operating properly.
The flex fan ( as in picture) were primarly sold for racing applications.. these type fans saved HP at higher rpm,,,then the public used them too!,,,the race cars had trouble at idle with temp,but the actual 1/4 mile- race was not the problem until the end and back to idle..
