Fan keeps flexing and cutting the wires.

[Jeff Johnson]

2006 with a 5.9. I've fixed this stupid thing so many times... I've fixed it at least five times. I've bent the metal bracket so it's almost touching the radiator. I've encased the wires in a rubber hose so they can't rub on the radiator. And the fan still flexes enough to rub on the hose, rub through the zip ties, rub through the hose, and cut the wires. And the metal bracket has all of the paint rubbed off. It's not all of the blades doing it - only three of them. Is this a normal problem? Is there a good replacement out there?

 

[AH64ID]

That’s not normal, I’d be looking for the source of the flex.

Has the truck been wrecked?

 

[Jeff Johnson]

I've never seen any evidence of a wreck. But, if it were from a wreck, I'd expect to see something while turning the fan by hand. The fan is a good 3/4" or more away from the wires while the truck is not running. But I definitely have three blades that flex into the wires while it is running. As for the source... they are plastic so...

 

[Ozymandias]

Is it an OEM fan blade and clutch?
It's the only thing I can think of there is that the blades are to flexible.

 

[Jeff Johnson]

The fan is stock, but the clutch isn't. When I got the truck, it already had wiring "repairs" done to the clutch (twist together and electrical tape). The wire was also rerouted, but it was broken when I got it. I think the old clutch was aftermarket, but it appears to have been a good one - it was stiff enough without the harness that I didn't know it was broken. I had a friend talk me into fixing it "right" and that's when all of my troubles started.

I just finished fixing it again. The three blades that have rub marks were probably out 1/8" - 1/16" from the others. I tried recurving them a little with a heat gun. They did move, but I don't know if they will stay.

I watched the fan from underneath while the truck was idling. The blades are a good distance away from the wires. Whenever they get cut, it's always at highway speeds now. The harness is ziptied to the radiator in 6 spots - every other row up from where the bracket curves. I don't think it's the zipties coming loose. I really think the blades jump when the fan engages at more than 2,000 rpm.

 

[Bromiley99]

Fan hub bearing? Just one more thought.

 

[Jeff Johnson]

I checked that while I had everything apart. It's tight - no wobble. And, like I said, I watched the engine run at idle. There is a good 3/4" of clerance. Since the wires don't really have room to move, and the bearings are all tight, and it's only three blades, and It's not a common thing, I'm going to go with the theory that someone did something to the fan in the past and it's now defective. It has a jasper engine, so someone could have easily set something on the fan during the swap and damaged it.

 

[CharlesinGA]

I replaced the fan on my '03 (same parts I think) as the old fan had nicks on each blade at the base from the water pump coming apart right before I got the truck. I don't trust any damage to a fan, so I replaced it. It was $150 in 2018. My old Ford Ranger plastic fan got cracks in the base of the blades and I replaced it right away, when I discovered them.

Charles

 

[Jeff Johnson]

Yeah, it's not a trivial cost to replace the fan. I'll see how my "heat gun" repair goes and replace the fan if it gives me a problem again. I have an aftermatket electric fan in there on a thermostat, so I'm not dead in the water if it breaks. But it sure is nicer when that big, mechanical fan is howling up front.

 

[MGreer]

The fan clutch could be the wrong one. In MY 04 there are two types of fan clutches, based on build date. I thought after MY 04 they only had one style. Yours should have metal protecting the wires with a heavy duty bracket at the bottom. I looked at rockauto and it shows the heavy duty/correct fan clutch except one, which doesn't have the protective metal.
It's possible someone has installed the wrong clutch.

 

[Jeff Johnson]

It's possible that someone installed the wrong one in the past, but I installed te last two - one of them being flat out defective. This one has a metal "guard" towards the top and another metal guide/bracket towards the bottom. As far as it being heavy duty, I would strongly debate against that. If you read up to my earlier posts, I stated that I bent that metal bracket to give more clearance from the fan and I have 3/4" clearance while the truck isn't going down the road. I also added the extra protection of encasing everything inside a rubber hose before zip-tying everything to the radiator. Nothing moves (except for vibration) until some of the fan blades creep forward 3/4", rub through the zip ties, grab the hose and the wires, and start cutting stuff.

I'm going to start doing regular inspections to see if I can catch broken zip ties before I have issues but, short of mounting a go-pro in there, I don't see how it makes sense to blame it on anything other then a defective fan at this point.

 

[Wiredawg]

The price of a new (correct) setup may start to look better as you keep fixing this. Sometimes wrong cannot be fixed. Please let us know how this turns out.

 

[Jeff Johnson]

I imagine you are referring to the Ford 7.3 fan clutch conversion? Because, at this point, the only thing that isn't new is the plastic fan. New water pump (not that that would matter), new fan clutch, new radiator, new belt...

 

[BigPapa]

Can you trim 3/4" off the blade tips?

 

[Jeff Johnson]

In theory, sure. But it wouldn't do anything to help this problem. The blades are flexing forward toward the radiator, not stretching out and getting longer.

 

[Ozymandias]

What a minute, you say you Ziptied that cable to the radiator?

 

[Jeff Johnson]

Yes. I believe I posted that at least three times.

 

[Ozymandias]

Well that won't work then as the radiator is fixed to the frame and Fan & half of the Shroud is fixed to the engine and moves around while driving. There is a lot of movement between these two units, that's why Ram with the 04.5 MY changed to the split system. Right now your engine is tearing on that wire with every load change.
It's not the fan blade that moves to the wire, it's the wire that moves to the fan blade.

 

[Jeff Johnson]

I can see where your point of view can have merit, but it's not showing up in experience. True, the fan, 1/2 the shroud, and the bottom part of the harness are attached to the engine, which is separate from the radiator. But the first point of contact for the blades is the metal bracket - which is bolted to the shroud mount - which is bolted to the engine - as is the fan. It's all one unit as far as that goes.

The first time I put in the new clutch, I had no reference since the old clutch wire was already torn off. I put it all together without zipties and I didn't make it one pass around the neighborhood before the wires ripped. Now I get 2-3 weeks.

If the problem were flexing of the engine/radiator combo, it would be more pronounced at low speeds - when taking off from a light, especially during a non-graceful slip of the clutch pedal. But the reality is that it happens while cruising at highway speeds - when the engine/transmission are fairly constant to one another.

That would be a good theory to look at if the evidence didn't point away from it. But it does give me a good excuse to look at my motor mounts. I couldn't tell you if they're any good or not.

 

[seafish]

Well that won't work then as the radiator is fixed to the frame and Fan & half of the Shroud is fixed to the engine and moves around while driving. There is a lot of movement between these two units, that's why Ram with the 04.5 MY changed to the split system. Right now your engine is tearing on that wire with every load change.
It's not the fan blade that moves to the wire, it's the wire that moves to the fan blade.

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