Fan Clutch FIASCO!!! - Dealer still can't figure out why fan clutches are failing!

[GShail]

As I have previously posted, my truck is going through fan clutches at the rate of about 1 fan clutch for every 5,000 miles. The dealer has been replacing them under warranty but we are talking about fan clutch #6, and this is getting REALLY OLD! In replacing the fan clutch I feel they have been treating the symptom rather than the cause. I had the truck in briefly yesterday at a local independent diesel shop and like the dealership, the local shop thinks everything (DRB) simply points to fan clutch failure.



The truck was at the dealership ALL DAY and they have no freaking clue as to what is going on with these fan clutch failures. All they can tell me is that fan clutch needs to be replaced. Hopefully tomorrow the truck will get a look over from one of the roving DC technicians in the state that troubleshoots particularly difficult problems for the various dealerships in the area.



Coolant is good. Signals to the fan clutch are good. All the fins on the AC, Intercooler, and Radiator are clean and flow air freely. The ground wire from my TST has been relocated from the battery to the inside dash frame. The pulley is not out of round. There appears to be no damage to the fan itself.



If the pulley is good, could the fan itself be out of balance possibly?



I have no ideas but I need to get this truck up and running.





What irks me the most is that the dealer is hinting that while they will replace the fan clutch again this time, next time it fails I am s. o. l.





Don't I have a beef, even if I am 45,000 miles out of warranty? I still owe about 22,000 on this truck but I am not too enthused about paying for a truck that the manufacturers dealerships can't fix.



The real bummer is that in the absence of this fan clutch fiasco, my truck has never ran better with more power, good mpg and cool EGT's. My Super Phat Shaft 62/14 has made this truck a towing dream.



Please wake me up from this nightmare. I need pointed in the right direction.

 

[rbattelle]

If the pulley is good, could the fan itself be out of balance possibly?

[



I think so. Tell them you want them to either balance-test the fan (they will not be able to do this) or replace it.



-Ryan

 

[GShail]

The fan looks good, but I suppose that looks don't mean a thing. In the absence of being able to do a fan balance test, I suppose replacement is neccessary since nothing else is turning up as the culprit. Nonetheless, I don't like the idea of just throwing parts at it! What the heck, it's only money. If that would work, I am more than willing to try it.

 

[rbattelle]

Has the same dealer done all the fan clutch installs?

 

[GShail]

No, the same dealer has not done all of the fan clutch installs. 1 was done in Idaho, 2 in Riverside, CA and 2 in American Fork, Utah. Presently, my truck is at Doug Smith Dodge in American Fork, UT.

 

[GShail]

Is there any wat to go with a custom radiator setup or maybe just an aftermarket electric fan? Horton apparently no longer makes a setup for our 3rd gen Dodges.

 

[GShail]

Today I am going to make phone calls to every diesel shop I can come up with to see if anyone knows why these fan clutches are failing.



Do any of you daytime TDR perusers have a clue as to what could be the problem with these fan clutch failures?

 

[GShail]

Anyone? Bueller?

 

[RankRam]

If the pulley is good, could the fan itself be out of balance possibly?

If the pulley is good, I would have to say the fan is out of balance. Have you suggested this to your dealer? I would be willing to bet on it.



But then again I'm from Nevada and we bet on pretty much everything.

 

[GShail]

Today I called 9 specialty shops all over America. Piers Harry, Huckstorf, Liberator, Jannetty Racing, Scheid Diesel (all three locations), JH Performance and Wentland Diesel. Everyone I called was very courteous and cool, but no one was able to offer much help. I guess I will have to throw parts at this thing and hope for the best. Everyone I talked with said pretty much the same thing, "never heard of such a problem, is it a mopar part?, are your fins clean on AC, Radiator and Intercooler?, coolant good?, is it getting the correct Fan Pulse Width Modulation?, etc. , etc.



Yes, Yes, Yes & Yes.



In the absence of any real trail to follow, I suppose I will have the blades replaced and the hub too, along of course with the new fan clutch.



When this doesn't work, what then?

 

[67guzzler]

When this doesn't work, what then?

Are you just venting? I mean, nobody here is going to say, "I got it! I got the answer. " If you called 9 shops and they don't know, you don't know and nobody here who has posted so far knows, maybe nobody knows.

I guess I will have to throw parts at this thing and hope for the best.

Yes -- sometimes that's what it takes. You replace all the related parts and then if the problem is fixed, you're done. You never end up getting the satisfaction of knowing what part was the problem. Sometimes that just happens.



Your frustration is bleeding out at the people here on the TDR who would gladly help if they could. But nobody really knows. So just replace all the parts and then see if that fixes it.



In the meantime, why don't you at least thank one of the people who have posted providing you with suggestions trying to help you. They didn't get the $35. 00 you paid for your TDR membership.

 

[GShail]

Oh, I am very thankful for all the suggestions I have received from everyone. Thanks for reminding me to be thankful.

 

[GShail]

Shawn Liberator @ Liberator Performance & Steve @ Wentland Diesel were particularly helpful. Also mega props to all the TDR guys who have been helpful!

 

[dmurdock]

Have you looked / Have the dealers told you what actual part of the clutch is failing?



You could always go to a clutch-less flex-a-lite but they are extremely loud and may overcool the engine.

 

[EStoller]

Just an idea, if the clutch is electric and not getting all the current it needs it may slip, generate a lot of heat and burn up. If it is electric, check the voltage at the clutch when ingaged. The problem may be in the wiring ahead of the clutch, if it is electric.

 

[GShail]

In the absence of being able to determine the cause of this fan clutch problem I went ahead and replaced all of the related parts. New fan clutch, new cooling fan, new idler pulley bearing, new fan pulley.



Being from Idaho & not being much of a betting man, I wouldn't bet that this will be a long term solution . . . . but I'm hoping.

 

[R C Cola]

Fan Clutch - Stray Thoughts

Sounds like most all bases have been covered. Hope it is now fixed. If not. .

I would consider if it is possible to use the old style with no wires. There may be a way to fool the computor into allowing you to do this. The old mechanical units are pretty much bullet proof ! From reading your posts it sounds like you know where to keep the RPM's for a happy heavy tow, but I will mention it here since it is very common. Some new users of chips of all brands are so happy with their new power and torque that the tendancy is to

lug the engine (2100 or higher) with a heavy load. Most of our trucks torque peak between 1700 and 1900 and seem to run cooler in that range. Not sure exactly where your torque curve is though.

I had this problem with mine when I had the pump turned up, the power was there but the engine overheated, dropped a gear and the problem went away. Good Luck R C

 

[MCecil]

I've read most of your posts on this topic and have a thought about a possible cause I have not seen discussed.

First this disclaimer: I am in the early stages of learning about the CTD and do not claim any expertise regarding the Cummins as configured in our Dodges. However, I do have an in depth knowledge of semiconductors, pulse width modulators (PWM), their associated drive circuits and load current characteristics of reactive loads.

Assuming your fan is not creating an excessive load on the clutch and given you have essentially replaced and/or tested all the mechanical aspects, it leads me to believe you may have a drive current issue. If the coil is supplied with insufficient current, the clutch may not engage with sufficient coupling force to overcome the load demand of the fan. This would result in slippage, leading to excessive heat, leading to eventual clutch failure. This is somewhat analogous to someone riding the clutch pedal while driving.

You have said that the dealers have checked the PWM and given ranges of 15-99% duty cycle at various times and functionality of the clutch. This was done on a logic analyzer and they did not check the actual drive current to the coil, right? If this is true you could possibly have one of at least two different but related problems either of which could be the root cause of failure.

The PWM signal, eventually, drives a current amplifying semiconductor supplying the coil current. This device can fail completely, or its characteristics can be degraded by a number of factors ranging from manufacturing & packaging, to handling, to final assembly of the end use product, to the working environment( usually heat).

Since your fan does work when the clutch is replaced and subsequently fails over time, it just might be insufficient drive current causing the clutch to slip under certain circumstances ending in the eventual failure. The most likely causes could be either a degraded current driver or resistive wire terminations, that is if this is, indeed, the root cause. Both would be consistent with the type of failure over time given the work that has been done without favorable results. These are avenues that might prove worthwhile investigating with the failure and maintenance history to date. Hope this helps you some.

Enjoy your day and God Bless,
Merv

 

[rbattelle]

Assuming your fan is not creating an excessive load on the clutch and given you have essentially replaced and/or tested all the mechanical aspects, it leads me to believe you may have a drive current issue.

Translation: you might need a new ECM. I believe the PWM circuitry is contained within the ECM itself.



I've never seen a current spec on the fan clutch signal, so even if you could test it there'd be no way to know if it's good or not (unless you compare it to another truck).



Have they checked the resistances in the fan clutch wiring harness against those listed in the powertrain diagnostics manual?



-Ryan

 

[GShail]

I have a relativeley new ECM that was replaced 4 Fan Clutches ago. One of my injector wires under the valve cover was fried and I was told this was connected to the failure of the ECM. ECM was replaced at that time along with the new injector wire. So far no porblems from that direction (injector wires, ECM), at least none that I know of. Now I am wondering more about the injector wire frying and taking out the ECM and all of this being related to the fan failures.



The resistances in the Fan Clutch wiring harness were checked previously but I will check them again.



I have long thought that some kind of electrical something has been the culprit all along, but I have little to no expertise in things electrical. I am going to take the truck into the specialty shop (Industrial Injection) again on Monday and see if Big Country (nickname for their best technician) can help me figure this out.



P. S. I am really very appreciateive for all the help being offerred. TDR rocks!