It has happened to me! (Dreaded Fan Sensor - Crumbling Hose!)

[TJC]

I felt well enough to modify the cable bridge to the fan clutch sensor this afternoon. Some (many?) may call this overkill, but I am hoping to put it out of mind for good. We'll see soon enough I suppose.

Just in case this fails, I saved all the old parts in my 2020 Ranger box in the garage.

Here is the original cable bridge (for lack of a better term). We have all heard of the hose failing and the reason is still unknown. I inspected my hose and it is good condition. That said, folks have had sudden unexpected failures.

I started with the purchase of a 10" 90 degree silicone hose. These hoses tend to hold up well long term. I carefully removed the old hose and used it to pattern the new hose. To get the mild bend, I formed and then inserted a soft copper 1/4" ID pipe into the silicone hose up to the 90 degree bend. It was a snug fit. Here is the result (right image).

And here is the hose installed.

Next I thought about how to protect the cable. I considered simply zip ties, but decided to run it through 3/8" fuel line. I split the line with a razor knife and inserted the cable. The yellow zip ties compress the cable, the heavier black zip ties secure the hose protecting the cable to the silicone hose bridge.

If the hose is simply decaying this will correct that problem. If the sensor is catching on the shaft, the bridge should be strong enough to withstand the torque unless the sensor actually freezes to the shaft. Short momentary tugs shouldn't stress the hose.

Once I completed the modification, I checked binding of the sensor and started the truck to validate the sensor moved freely. Then went for a test drive. All normal. Hopefully this puts the issue to bed, but only time will tell.

I still hate the design. It screams amateur engineering to me.

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[Dr. Zaius]

I felt well enough to modify the cable bridge to the fan clutch sensor this afternoon. Some (many?) may call this overkill, but I am hoping to put it out of mind for good. We'll see soon enough I suppose.

Just in case this fails, I saved all the old parts in my 2020 Ranger box in the garage.

Here is the original cable bridge (for lack of a better term). We have all heard of the hose failing and the reason is still unknown. I inspected my hose and it is good condition. That said folks have had sudden unexpected failures.

I started with the purchase of a 10" 90 degree silicone hose. These hoses tend to hold up well long term. I carefully removed the old hose and used it to pattern the new hose. To get the mild bend, I formed and then inserted a soft copper 1/4" ID pipe into the silicone hose up to the 90 degree bend. It was a snug fit. Here is the result (right image).

And here is the hose installed.

Next I thought about how to protect the cable. I considered simply zip ties, but decided to run it through 3/8" fuel line. I split the line with a razor knife and inserted the cable. The yellow zip ties compress the cable, the heavier black zip ties secure the hose protecting the cable to the silicone hose bridge.

If the hose is simply decaying this will correct that problem. If the sensor is catching on the shaft, the bridge should be strong enough to withstand the torque unless the sensor actually freezes to the shaft. Short momentary tugs shouldn't stress the hose.

Once I completed the modification, I checked binding of the sensor and it moved freely. The started it up and test drove. All normal. Hopefully this puts the issue to bed, but only time will tell.

I still hate the design. It screams amateur engineering to me.

So nothing is actually going through the hose, it's just there to be a support for the wiring?

Why not just use the copper piping instead?

 

[TJC]

So nothing is actually going through the hose, it's just there to be a support for the wiring?

Why not just use the copper piping instead?

Correct, there is nothing going through the hose. It is simply there to route the cable above the belt and keep the fan sensor from spinning with the fan/fan shaft.

There are two studs that the hose connects to. There is still flex in the hose as well. I think the flex is needed. That fan speeds up very rapidly, exerting torque on the sensor. I think you need flex to dampen the torque. Both ends of the silicone hose are free to flex.

I needed the copper to match the bend in the original hose and keep stress off the sensor. A happy byproduct is that it strengthens the bridge.

 

[airline tech]

So nothing is actually going through the hose, it's just there to be a support for the wiring?

Why not just use the copper piping instead?

While copper piping or any rigid support is a possible solution, until we can get some kind of verified information the true reason for having the hose in this design.
The flexibility is there for a reason buy why ?‍
I have dug deep into the depths of the web and cannot find any verified description of the reason for the hose vs solid mounted support.

What I do know, is that with the truck running and you VERY CAREFULLY reach down and place your hand on the module you can feel the (vibration) of the shaft spinning at the module, you can also rotate the module (side to side) without any pulling effect.
Now this is with a normal operating Fan Clutch, the unanswered question is what change is causing the module to spin.

1. Hose breaks - wire gets caught on the hub bolts and pulls the harness.
2. Wear at the race on the module, binds the module to the shaft - module spins.
3. Clutch Fan - Engage / Disengagement - Issues, creating abnormal stress on the shaft, (rock - side to side)
4. Clutch Fan Bearing - Failure causing the Fan to rock backwards, pinching the module between the fan hub and the attaching nut.

If you will note, no one is having and codes prior to the failure, so electrical control wise it appears to be working - so #3 can possibility be ruled out.

I have seen a post about this issue with only a few thousand miles on the truck, so brand new and had wires break.
This points to something more than just a hose breakdown, something else is the factor and we are just not seeing it. (YET)

So, would a solid mount cause more resistance on the module as it is resting on the spinning shaft?
Unknown Answer?‍

Until we can get one apart and see what is actually happening or Ford Tech who has replaced a few of these, to identify the root cause of the failure.
This is going to be an unknown answer.

 

[TJC]

The failed hoses that I saw appeared to have stress cracks or dry rot, not sure which.

I agree that we don't have a definitive answer.

My hose looked perfectly normal. I did move / rock the sensor with the new hose and it felt smooth. Operated normally when I drove it and no excess noise indicating stress on the bearing.

Re: #3
Maybe a bad batch of hoses. Flex would weaken and break at the points of flex stress. Bend anything often enough and it will fail.

 

[got3fords]

My hose looked perfectly normal. I did move / rock the sensor with the new hose and it felt smooth. Operated normally when I drove it and no excess noise indicating stress on the bearing.

Re: #3
Maybe a bad batch of hoses. Flex would weaken and break at the points of flex stress. Bend anything often enough and it will fail.

Did you also use new clamps? I am due for another trip to Ohio and need to check the health of this assembly.

 

[TJC]

Did you also use new clamps? I am due for another trip to Ohio and need to check the health of this assembly.

The silicone hose is 3/4" outside diameter. I used 3/4" stainless steel hose clamps. The Ford clamps on my Ranger were different, the engine side was a crimp on (not reusable), and the sensor side was a spring wire clamp that I could squeeze and spin around by hand. I used needle nose pliers to remove it.

If you attempt this, make every effort to keep any pressure off the sensor bearing. It needs to float.... less bearing wear. The hose simply holds the sensor in place.

 

[HeatXfer]

I'm thinking this might work as a replacement.

HPS Performance 3/8" ID, 10" Leg, 90 Degree Silicone Elbow Coupler Hose, High Temp 4-ply Reinforced, Black (HTSEC90-038-L10-BLK): Amazon.com: Industrial & Scientific

Your fix looks damn solid

This one's already halfway there. Looks like it would be easier to work with.

 

[TJC]

Your fix looks damn solid

This one's already halfway there. Looks like it would be easier to work with.

Thanks,

It may not really matter depending on the cause of the failure. I do feel better with this bridge than I did with the stock hose. If the hose is the point of failure I am better off. If the clutch is slightly catching I am better off. If the clutch failure is catastrophic it won't matter what hose is in place.

We really don't know where the problem is. It could be poor material (cheap hose), a mechanical failure of a bearing or clutch, or even a software bug.

Re: The hose
You might be able to cut the hose at the following locations to end up with something close, but not exact. The bend at the long end of the hose ( A ) that connects to the engine is an off plane angle bend. The bends on this hose appear all to be on the same plane. So to be safe you'll still need something inserted with the correct angle into the hose to insure minimum pressure on the sensor.

I will be the first to say that this is pure speculation. But forming the new stronger hose to the exact form of the original minimizes the risk.

 

[HeatXfer]

Thanks,

It may not really matter depending on the cause of the failure. I do feel better with this bridge than I did with the stock hose. If the hose is the point of failure I am better off. If the clutch is slightly catching I am better off. If the clutch failure is catastrophic it won't matter what hose is in place.

We really don't know where the problem is. It could be poor material (cheap hose), a mechanical failure of a bearing or clutch, or even a software bug.

Re: The hose
You might be able to cut the hose at the following locations to end up with something close, but not exact. The bend at the long end of the hose ( A ) that connects to the engine is an off plane angle bend. The bends on this hose appear all to be on the same plane. So to be safe you'll still need something inserted with the correct angle into the hose to insure minimum pressure on the sensor.

I will be the first to say that this is pure speculation. But forming the new stronger hose to the exact form of the original minimizes the risk.

Your fix looks every bit the final solution: flexible like the original, but much stronger. Plus the armored wiring harness should prevent damage there, IF your silicone bridge/shock absorber ever fails.

 

[TJC]

Maybe, but if the clutch sensor bearing seizes, it will most likely pull the cable until it breaks. Hopefully I will hear a bearing squeal well before that occurs.

 

[pboggini]

After watching this I went out to the shed and grabbed some guy wire for TV antennas to put in just in case. While putting it on in squeezed the hose just a bit on the engine bracket side and it split. Sigh. So I pulled it off and put the hose back on with a screw clamp. My hope is the safety wire is my safety net but the hose reclamped feels pretty solid for now.

I picked up an older ranger heater hose that has a nice 90 in a couple of places and some brake line. I'll build a new hose like @TJC did this weekend. It seems like the place this hose gave up was right where the flare is on that engine bracket.

That stock hose feels really thin like it's no more than vacuum hose durability.

Peterb

 

[TJC]

While putting it on in squeezed the hose just a bit on the engine bracket side and it split. Sigh.

I picked up an older ranger heater hose that has a nice 90 in a couple of places and some brake line. I'll build a new hose like @TJC did this weekend. It seems like the place this hose gave up was right where the flare is on that engine bracket.

That stock hose feels really thin like it's no more than vacuum hose durability.

You may be on to something. IIRC, I've seen failures on both ends of the hose, but if one end fails first it might take the other end with it as the sensor starts a death spiral for the hose and cable.

The engine stub was troubling to me as well. It doesn't flare as I expected, It looks like it was stamped and ends with a 90 degree sharp flange with the profile of the letter "T". Now imagine a cheap thin walled vacuum hose pressed over that and crimp clamped in place. Then think about the constant tug and flex when the clutch (de)activates.

Stress anything long enough and it will break. The hose is tightly constricted over that 90 degree flange and then tightly crimp clamped right behind it. That puts a lot of stress on a very small patch surface area right where the hose meets the edge of the "T " flange.

Poor design and poor quality parts.

The really good news is that you caught it before it failed, and that failure was imminent!

 

[pboggini]

I texted my friend who works at a Ford dealership up north and asked him to check in with his service reps. He said they are understaffed today so he will look for a time to chat with them but the also said they've sold 2 of these fan clutch assemblies in the last 2 years so he says it doesn't seem to be a huge demand item. I'll post more once he's had time to talk someone in service. I did ask if he could ask them if they've seen one where the hose failed or what the failure mode seems to be.

Mine is still holding and my plan is just a bit different than you @TJC . I'm going to use one of the rubber 45's from that heater hose I got, one of the 90's and then I'll do the first bit of a double flare on the 3/8" hard brake line so I can clamp it inside the two pieces of rubber. Looks like there are 2 90's I could use and 2 45's so I could make 2. Will send pics as I do this.

 

[TJC]

I texted my friend who works at a Ford dealership up north and asked him to check in with his service reps. He said they are understaffed today so he will look for a time to chat with them but the also said they've sold 2 of these fan clutch assemblies in the last 2 years so he says it doesn't seem to be a huge demand item. I'll post more once he's had time to talk someone in service. I did ask if he could ask them if they've seen one where the hose failed or what the failure mode seems to be.

Mine is still holding and my plan is just a bit different than you @TJC . I'm going to use one of the rubber 45's from that heater hose I got, one of the 90's and then I'll do the first bit of a double flare on the 3/8" hard brake line so I can clamp it inside the two pieces of rubber. Looks like there are 2 90's I could use and 2 45's so I could make 2. Will send pics as I do this.

The 45's may be too much angle. But once you get into it, you'll know more.

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