Stop fan-clutch for water crossing?

Wanting to know if the radiator fan clutch can be stopped during water crossings to prevent the fan from destroying the radiator. I imagine most people would say to get an electric fan. I dont know if there is a way to stop the radiator fan from spinning, short of removing the belt, but if the fan clutch was controlled by the engine coolant temp sensor, I may be able to install a kill switch somehow. I dont know how the fan clutch works and Im not at home so i cant look under the hood of my truck. Is this a viable option or just a pipe dream?

 

1st gen fan clutch has a bi-metalic strip (Or something like that) that when it reaches a certain temperature it will engage, the only way you can stop it from engaging is by cooling the metal piece.

 

Oh darn.. i thought it might be something like this. What if I stopped the engine and put a stick in the fan to prevent it from spinning -- would it burn up the clutch fan or would/could it freewheel?

 

That's just a terrible idea, something would break and it would likely be the fan blades.

 

Fan would be stopped while I would be putting the stick in - so when I start the engine, the fan would not move at all. I'm more concerned about the clutch burning up on the fan.

 

I understand that the fan would be stopped when you insert the fan, but I think the clutch would transfer enough energy to break a fan blade.

Before you try that on a trail I would go to autozone/Napa/oreilly or any other local place, get a replacement fan blade and then go home and try your theory.

 

Aye. I wouldnt dare try it out on the trail. I probably wont do this ever, but It would be nice to know what options I have in the future when crossing creeks. There was one time about 5 years ago when I drove (flew) through a creek with no concept of stuff being able to break. Luckily nothing did break then. If I have to do it again, I think ill just take the belt off to cross.

If I happen to try the theory, I'll post the results.

 

I not real sure why you are worried about a spinning fan in deep water.

Just how would it destroy the radiator.

Perhaps a plastic fan that is old and brittle could break if it was submerged at like 5000 rpm.

I myself would worry about the alternator and starter .

Then maybe Sharks !!

 

Because a fan hitting the water at speed will do A LOT of damage, including, but not limited to bending the water pump shaft. The old trick used to be to tie a rope or belt around the base of a fan blade and tie it to something secure in the engine bay. On plastic fans some people like to get a few wraps around the base of the fan to prevent all the energy from going to a single blade that may, but probably wont, snap. All that said your fan should freewheel like this, and to check it is easier than you might think. Go out to your truck, pop the hood, while the engine is OFF (door locked, keys inside, battery diconnected, kevlar gloves, and a bullet proof vest if you're in an osha state) grab the fan and turn it. If it turns without the engine turning or the pulley slipping on the belt you should be fine. Yes the spring will eventually expand and try to spin the fan, but this should do very little for a couple of minutes while you cross a river or stream. Besides that, your engine will cool down rapidly at this point as it will be partially submerged in a river.

 

Because the fan is behind the radiator and water is denser then air, when the blade hits the water, the blade will bend forward. Try swinging in arm like a windmill with your hand out/fingers straight/hand turned to imitate the fan blade angle. Keep doing it, faster, and faster, then let your hand go into a pool. Your hand will try to glide forward, much like the plastic blade of a radiator fan as it chews through your radiator

I'll try this... Thanks!

 

I really had no clue as I am scared to death of water. It is a long story!!

So of course there would be no reason for me to have learned this the hard way.

I am curious what keeps the water from just floating the vehicle away ??

 

Nothing. When the engine stalls is when your in deep shit. Bye Bye truck.

 

I've seen this happen on Fordyce Creek trail (no too far from the Rubicon). There are 3 deep creek crossings. On one, a jeep guy with a 'flex fan' (no clutch) tore up his radiator on the second crossing. He had to do a trail-repair by removing, then closing off the part of the radiator that was leaking.

I've seen electric fans fail completely on the trail, so I never wanted to do that.

I've heard of securing the fan with just a short piece of string, but never tried it. I did, however, drill a small hole in the tip of one of nylon fan blades, just in case I wanted to try it on the trail, but never had the need, so I don't know if the string would have been strong enough against the force of the clutch.

 

Part of the problem was the OP's statement that he "Flew" through the creek crossing....if you go at a slow steady rate you should not have any real issues with the fan. Done way to many creek crossings to count and never ate a radiator ( and yes, I've had water inside the 40). Both the trail and the vehicle will be happier campers if you just take it slow and easy rather than blasting through water crossings which can cause issues with both your vehicle and the trail.....part of that "Tread Lightly" thing that lots of folks seem to ignore.

 

Have you considered removing the factory fan and installing an electric fan with an on/off switch?

You can pull the fan and clutch, use shorter bolts to maintain the pulley on the water pump.

 

No help here but just had to share this
https://youtu.be/LC5ld79joIA

 

I have, but I would like to keep as much stock on this truck as I can. I am really in favor of the string method.

Yea... I know... In my defense on the "Tread Lightly" train of thought, I was actually on a dirt road where a seasonal stream crosses. Still, I was going way too fast.

 

There are a TON of factors to consider when crossing a substantial stream. First thing is 4 wheel drive. 99% of the time you want to engage it to prevent circumstances like the video above, that way even if the rear floats the front will keep going. Opening or removing your tailgate will also allow water to get into the bed faster to help this, but not eliminate it. You're also going to want to forde the river. This means you are creating a bow of water around your truck. The water level at your engine will actually be lower than it is outside your truck, until you stop. Stopping is when shit gets real. This is when the water level between the outside of the truck and your engine compartment become the same. Fan blades hit water, stock intakes suck up water and engines hydrolock, etc. If you do stop you have to weigh the pros and cons of shutting the engine off. If the fan hit the water hard the pump's shaft may be bent, and the fan may be missing pieces making it unbalanced, however as soon as the engine is off you no longer have positive pressure in the exhaust which means you may not be able to start your truck while it's in the water. If it's a fast moving current it could litterally slowly take your truck down stream or flip it, and if it's a sandy bottom it will pull the sand under your truck away and try to bury it. This is why I would tie off a fan, or unplug an electric one. If i have to stop I know the incoming water isn't going to damage it, it will keep the motor cool, and i can stop without having to shut off the truck until the water hits the ecu and does it for me. All that said, its best not to enter rivers unless you're prepared or have no choice. Even then you should do all you can to assess the depth, get a tow strap or winch line ready, etc. And if you're an atheist, you might want to convert and start praying a little bit before you go in.

 

I think the string or rope will work for very short times of a minute or two at most but more then that would most likely burn up the clutch and destroy it. it is just designed to slip "some" and the internals cant really handle being completely prevented from turning altogether.

maybe if you converted an old chevy fan clutch, I think those were designed to slip and free spin a lot more

 

Great info 2008taco. I will avoid most water crossings but the pepper mentality in me thanks you for this potentially crucial information. I may even print this out and laminate it and keep it in the truck just in case along with the string.