I don't have experience with fiberglass flex fans but have over 600K miles on a stainless flex fan hard mounted no clutch. The water pump spins app 6% faster than the crank and I spin to 5,400 rpm's. A couple times a year I look for cracks starting on the blades, biggest hazard so far over the years is reaching near the fan with the motor off and nick a knuckle.
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Well the guys who do tuff truck comps in the water and mud..(tank trap) type stuff use solid mount fans they are the most durable...no flex....no plastic.
The only other option you have is to mount it in the bed like the baja guys do and run an electric which is what i would do if i were going to do mad offroading.

 

I'm a little surprised no one has brought this up yet:
Flex fans are a low cost alternative to clutch fans. The intent is to save fuel by reducing demand on the engine. With a flex fan the blades reduce drag by flattening out at higher RPMs. That's just fine on the highway, plenty of airflow without the fan.

Trail driving is a different story. A close to stock motor with stock gearing requires enough RPMs to flatten the blades of a flex fan. A true 4 wheel drive moment won't supply the airflow the cooling system really needs. Unless you have a motor and gearing that let you crawl anything just above idle, a flex fan is the wrong thing for the trail.

FWIW, I'm going electric. Taurus V-6 fans are cheap and plentiful in the boneyard, as are 12 volt relays and temp switches. I already have a high amp alternater. Past fabbing a sheet metal shroud to cover the radiator, the hard part is deciding what tricks I don't want the set up to do.

 

I had the same experience as Hypoid with a flex fan, except for me it was towing type duty. Engine at high RPM but not alot of road speed. I ended up getting rid of the flex fan and going to an electric.

 

With a stainless flex fan the pitch is like 60 degrees for high flow at low rpm's, the reason they are called flex fans. I pull a 4 horse trailer with 3 horses on the ranch, hills at speeds under 5 mph around 95 degrees temperature without cooling problems. Same conditions with the stock fixed iron fan resulted in overheating. All tests including a clutch fan with a fan shroud, 5 row stagger radiator. I run what works for me.
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going from a stock fan to a clutch fan or flex is barely noticeable not to mention not worth the time as far as horse power. Only going to an electric will net you any real power. I read an article in 5.0 magazine once that tested all the fan types with a dyno, a clutch fan was like 2 hp difference if that. The only reason i suggest going with the solid fan is, if your gonna be up to the carb in water your electric will short out unless its raised in the bed behind the cab.

 

I'm no fan of the flex fans either. As noted above, high revs and not much forward speed will cause overheating. Additionally, I've also seen a flex fan lose a blade...not a pretty site. As someone else noted, I wouldn't stand beside a flex fan...that's just good advice period though...I try not to stand inline with any fan.

 

so you guys would suggest that i get a stock fan as a replacement then?

 

safety first

 

That's good info, you have to question the boo-rah advertising.

Hmm... There's one I didn't think of; submersion. Some of the fans are pretty well protected for a damp environment. I have seen a few running after being drenched in coolant-not the same.
One advantage of an electric is a manual shut off in the cab, no desire for a rotating mass in the wet stuff. While we are on the subject of submersion, how do you protect the alternator, shut down the field voltage?

All these details: Good thing I'm easily entertained!

 

No idea.....but i do know that the connections on a fan are protected atleast reasonably well...but I wouldnt trust it if i were submerged or even after i came out...even with the shut off switch. From the looks of your gallery I would go with a stock fan that has been closely inspected it looks like your pretty rough on it and you need something tough.

 

Alright, I suppose that I will go to a junkyard and get myself a stock fan. I will try to get some pics in my gallery of the "puddle" that i killed my first radiator in.

EDIT: Got some of the pics on, I am sure you guys wont have any trouble finding the pictures that made the fan "swim" into the radiator.

 

After you install the fan check the blades track to prevent vibration and future pump bearing failure.
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didn't your mother tell you not to play in puddles? LOL

 

Well the bottom line is Dependebility.....and the Old style Jeeps just ran a standard straight fan on them..some with a shroud and some without, Depending on what they were going to be used for....

When I was in the Military we would take those old jeeps and pull a utility trailer behind them with are gear in them..and run them thru river's right up to where the air snorkel was, That came out of the side of the hood 2 feet in the air... We got them stuck on occation because of hauling the trailers behind.. but we would pull them out with a 10 wheel duece and a quarter... I dont think you'll have any problems with a straight fan and a shroud..I too looked at some of your pics.. And you drive that 62 like it should be driven!!

Good Luck and keep us posted!!

Russ