Clutch Fan Question

[Chile3]

2004 2500 2WD 5.9L. What is exactly the function of the component that appears to be an electrical motor on the front of the OEM clutch fan? Other sources (videos etc) have referred to this as a motor. Seems to me that it must be some sort of valving device along with the sensors (probably Hall Effect) that provide the actual fan RPM to the ECM/PCM. Am I correct here or do I not understand how this elctro/viscous clutch functions?

Any and all assistance is greatly appreciated.



Thank you

Chile

 

[AH64ID]

It’s an electronically controlled viscous clutch.

 

[Ozymandias]

Where the old clutches has a bi-metal valve to control the flow of the fluid inside the clutch this one has an electrical activated valve. It also knows the exact speed* of the fan. The ECM commands the fan speed by several parameters, so it can even come on when the coolant is at a lower temp but the ECM expects a sudden raise.
Example: WOT up a hill.

*it isn't a simple on of switch like the old ones, this one ramps up to a commanded fan speed and matches it exactly, independent from the engines rpm. So the old term "the fan kicks in" isn't applicable anymore to this version of clutch. Most time yiu don't even notice the fan because it stays under the limit to recognize it as a driver.

 

[Chile3]

Where the old clutches has a bi-metal valve to control the flow of the fluid inside the clutch this one has an electrical activated valve. It also knows the exact speed* of the fan. The ECM commands the fan speed by several parameters, so it can even come on when the coolant is at a lower temp but the ECM expects a sudden raise.
Example: WOT up a hill.

*it isn't a simple on of switch like the old ones, this one ramps up to a commanded fan speed and matches it exactly, independent from the engines rpm. So the old term "the fan kicks in" isn't applicable anymore to this version of clutch. Most time yiu don't even notice the fan because it stays under the limit to recognize it as a driver.

 

[Chile3]

Thank you for your timely response. So the device on the front of the fan clutch assembly is not actually a motor to drive the fan to a commanded rpm rather a valving device to control the internal fluid coupling to achieve a fan RPM determined by the ECU by other parameters. In all cases the commanded RPM will be below the actual engine rpm for the reasons you stated. Am I getting closer to an actual control algorithm description?

Thank you again,
Chile

 

[AH64ID]

The rpms can be greater than engine rpms if the fan clutch is locked up at 100%.

 

[Ozymandias]

Thank you for your timely response. So the device on the front of the fan clutch assembly is not actually a motor to drive the fan to a commanded rpm rather a valving device to control the internal fluid coupling to achieve a fan RPM determined by the ECU by other parameters. In all cases the commanded RPM will be below the actual engine rpm for the reasons you stated. Am I getting closer to an actual control algorithm description?

Thank you again,
Chile

Exactly this.
Because of the pulleys the fan speed can be higher then the engine rpm.

 

[Ozymandias]

As a side note, you'd need a 20hp electric Motor for this size fan blade. You don't want to imagine the wiring this would need at 12V.

 

[Chile3]

Thanks to all for your assistance. This operative mode is much clearer now.

Thanks again,
Chile

 

[Grumpy8811]

As a side note, you'd need a 20hp electric Motor for this size fan blade. You don't want to imagine the wiring this would need at 12V.

View attachment 143072

yeah, back in the day my employer added some really nice electric fan setups to some of their existing vehicles that formerly had hydraulic fans... these things had 8 electric fans, and a electonic controller for each, could do 2 fans motors on the charge air cooler and tickle the 6 fans on the radiator separately.. but this fan setup necessitated the use of a 24V 400A alternator as compared to the standard 24v 250A alternator.. you could test the fans by pushing a button that would enable them to run backwards at full speed in order to clean the radiator... and if all 8 fans were on at full speed it sounded like a jet plane taking off..

 

[CharlesinGA]

Basically the hub on the front is the electric slip ring connection from the wires to the electric valve. Make sure the plastic stiffner is properly installed on the wiring and that the wire is properly mounted/connected to the shroud so the wires cannot get into the fan.

Charles

 

[Chile3]

Thank you to all for your assistance. I have received a new Hayden fan clutch for my EARLY 2004 Ram 2500 5.9L 305Hp truck. I additionally invested in a new hub bearing. Yes, I have a shop press to make the change. That is the least of my problems at this point. For the life of me I cannnot get the fan shroud extracted from the truck. I have the DRM for this truck and have attempted to follow it. My issue is that the coolant recovery container is attached to the fan shroud and wont clear the upper radiator hose and what appear to be transmission cooling hoses lower driver side. I have the lower portion of the shroud removed. It seems that the fan clutch assembly could possibly be extracted by dropping out the bottom. I have a vehicle lift so access from the bottom is not an isssue. The DRM states that the fan clutch and shroud assembly (minus lower section) must be removed together upward. If this is the case then the fan clutch must be removed from the hub assembly to attempt that procedure as well. My problem is that it seems that even if the fan clutch assembly was absent it doesn't seem the residual shroud assembly can be extracted upward with the coolant recovery container in place.
From the DRM and what i have read it appears that the early 2004 truck shrouds are a different design than later models 2004.5 and up. I think I now understand why the coolant recovery tank was moved elsewhere in the later models.
I am stuck here. I would greatly appreciate any experienced suggestions relative to my dilemma.

Thank you in advance,
Chile

 

[Ozymandias]

Are there no videos on YouTube for this?
I've an 04.5 so I can't help you directly with this issue.

 

[User113]

This is from a 2003, might help? Shows the coolant bottle staying in place, just detached and pushed out of the way.

BTW, my 2004 service manual also states "(2) Remove coolant recovery container (Refer to 7 - COOLING/ENGINE/COOLANT RECOVERY CONTAINER - REMOVAL)." as a separate step before removing the lower shroud in step 3 and the upper shroud in step 9, but nowhere was I able to find how to remove the diesel coolant recovery container!


2003 DODGE CUMMINS RAM FANCLUTCH REPAIR

 

[bcbender]

From the DRM and what i have read it appears that the early 2004 truck shrouds are a different design than later models 2004.5 and up. I think I now understand why the coolant recovery tank was moved elsewhere in the later models.

The 2004.5+ trucks are mounted to the engine and even more of a headache according to my friend that has one.. We did the clutch in my 04 and the hardest part was getting the lower shroud out I recall (mine was busted).. I think I pulled the upper hose and the recovery bottle but not sure exactly..

 

[Chile3]

This is from a 2003, might help? Shows the coolant bottle staying in place, just detached and pushed out of the way.

BTW, my 2004 service manual also states "(2) Remove coolant recovery container (Refer to 7 - COOLING/ENGINE/COOLANT RECOVERY CONTAINER - REMOVAL)." as a separate step before removing the lower shroud in step 3 and the upper shroud in step 9, but nowhere was I able to find how to remove the diesel coolant recovery container!


2003 DODGE CUMMINS RAM FANCLUTCH REPAIR

Thank you for the referenced video. It appears that the upper radiator hose was indeed removed to allow displacement of the reservoir enough to remove primary portion of the shroud upward. I am headed to the truck now to pursue this approach. Will report back with BDA ( Battle Damage Assessment). Just Kidding

Thank you
Chile

 

[Chile3]

Thank you for the referenced video. It appears that the upper radiator hose was indeed removed to allow displacement of the reservoir enough to remove primary portion of the shroud upward. I am headed to the truck now to pursue this approach. Will report back with BDA ( Battle Damage Assessment). Just Kidding

Thank you
Chile

In addition I too noticed that the DRM conveniently ommitted the procedure for removing the "Coolant Recovery Container" for the diesel engine. I suspect that is due to the fact that they recommend removing the truck body from the frame in order to extract the 5.9L Coolant Recovery Container. Just Kidding Again-- I think.

 

[Chile3]

Update: 1. I removed the radiator end of the upper radiator hose and tied it back out of the way. 2. I moved the coolant recovery reservoir (CRR) as much as was possible from the top. 3. I lifted the truck and was able to disengage the CRR tab from the primary fan shroud which allowed me to move the CRR a bit more outboard. 4. I began pushing the shroud up until I realized that the lower radiator hose would also have to be removed. Why? BC the plastic portion of the shroud that hold serves as mounting structure for the fan clutch wiring bundle (passenger side low on shroud) will not clear the lower radiator hose if the hose is installed. 5. Drained radiator and removed lower radiator hose. 6. I was now able to move shroud laterally enough to clear the CRR and by tipping was able to clear lower radiator outlet. 7. Lowered truck and was able to snake shroud between the fan and the radiator and remove the shroud upward and out.
Notes: 1. I fabbed a cardboard protector for the radiator 2. I did not have to remove the fan clutch along with the shroud as mentioned in the DRM. This made loosening and removing the fan clutch assembly much easier. 3. I determined that it would not feasible to remove the fan clutch out the bottom as it appears that the fan clutch assy would not clear the harnonic ballancer without significant contact with the radiator fins. Besides, with the fan shroud removed it was a straight forward process to remove the assy from the top. 4. The DRM is accurate relative to this process only to a point. I had to perform several additional steps to complete the removal.
Side story: It turns out that a BDA (Battle Damage Assessment) is in order. After removing the all tension from the serpentine belt and before I removed the fan clutch I "felt" all rotating mechanisms in search of any suspect belt driven components. I found nothing suspicious. After removing the fan clutch I removed the fan hub bearing assembly as I had previously decided to replace the fun hub bearing regardless. I discovered that the fan hub bearing was trashed. Very rough and when free spun by hand made a high pitched "metal on metal" noise. I cannot explain why I did not denote this when turning the hub by hand prior to removing the fan clutch. Perhaps the relaxed serpentine belt was still in contact with the pulley. Can't say.
Once I am satisfied that I have accomplished this task in it's entirety I am considering posting a sequential checkilist documenting my steps. It seemed that while there are a multiple references for this task relative to late 2nd gens and 04.5 and later there was a dearth of info related to the 03s and early 04s. I can attest that the processes are definitely different.

Thanks to all again for your experienced assistance.
Chile

 

[Topzide]

@Chile3, As you're finding out, the DRM is written by engineers and then the techs have schooling to learn the stuff 'between the lines'! Glad that you have made progress and found issues that you were looking for. Hope it all goes back together better than it came apart for you. Amend the DRM as needed!

 

[CharlesinGA]

I have removed the fan and clutch assembly twice simply by disconnecting the wire harness, and pulling the scrivets that hold the lower shroud portion in and removing it, then after unscrewing the fan from the hub, carefully, I lowered it out the bottom. Did this by myself. First time I used a real heavy 36mm open end on the fan and a aircraft rivet gun and flat set to hammer on the wrench and a pry bar slipped between a couple of the pulley bolts on the hub. I was removing it to replace the damper with a Fluidampr, and the second time, I finally decided to replace the fan blades due to damage when the water pump failed (prior to my buying the truck) i was jittery of the blades separating so I bought a new one and pulled the clutch and fan and changed it out. I also helped a buddy of mine remove his '04 fan to replace the damper with a Fluidampr also. It went much faster with two of us on it.

Charles