electric fan

[M Morris]

I hate to rehash this question if its been a hot topic in the past, but I need advice. My thermo bearing or what ever you call it has locked up. The fan is pulling hard all the time and with todays fuel prices I need to fix this, it cost me about 2 mpg. I have a 03 and my understanding is that this is a regular problem every 75K or so. The cost on the bearing from my dealer is $365. 00 and not covered under in the powertrain plan. I see flex a lite has a set up to replace the fan with electric fans. The set up looks good in pictures : but ????

Then when I call them they say it may not work if I also have an electric fan clutch ? Would my 03 have both ? (it a 6 speed BTW). what should I do ? I would rather have electric fans then be changing this bearing again.

Thanks in advance.

























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[rbattelle]

What, exactly, is wrong on your truck? I'm not familiar with the term "thermo bearing", so I don't understand what you mean by that.

I interpret from your post that the fan clutch has locked up. The fan clutch is electronically controlled.

Would your '03 have both what? Both a "thermo bearing" and a fan clutch? Again, I have no idea what a "thermo bearing" is, so I can't speak intelligently about that.

Member GShail, the king of failed fan clutches, is running the flex-o-lite electric fans now, as far as I know. He would be a good person to ask to chime in on this thread.

Ryan

 

[M Morris]

apparently I dont know what I am talking about either ? I only know what I am told about this. My understanding was that there was a bearing in the fan that was thermostatically controlled, and possible another bearing in the electric clutch- if the truck was equipped with the electric clutch. Even flex a lite says the truck may have an electric clutch or may not ? I just know that the fan no longer free wheels like it used to and I was quoted $365 for the bearing.

 

[jelag]

I own 4 trucks, from 250K miles to 12K miles on the new 08... . we have close to 500K miles on the 4 trucks total... we have never had a fan clutch failure on any of the trucks... Most of the bearings that are used in the air operated fan clutch on a class 8 truck (Horton Fan Clutch) are under $20 each... your number sounds high to me... . if it was one of my trucks we'd have it off and on the bench inspecting it... . and than the repair... .

 

[231jasonS]

I was told the flex o lite fans were only good if your not towing heavy. I dont think they move as much air.



But if not towing heavy or often the HP and MPG gain from an electric fan could be worth the $.



I know ADAM from WInspeed is running a 2nd gen flex o lite fan set up on his 900+HP 2nd gen (daily driver) and loves it. I have yet to see a 2nd gen kit in person but suspect its a nice product based on the 2nd gen ones ive seen.

 

[rbattelle]

apparently I dont know what I am talking about either ? I only know what I am told about this.

I can tell you with absolute certainty that your fan clutch is electronically controlled. It's called a viscous fan clutch, and a brief description of it's function can be found here. I can also tell you that, based on your description, the fan clutch is locked up.



Here's how the 2003 service manual describes the function of the viscous clutch:

The Engine Control Module (ECM) controls the

level of engagment of the electronically controlled

viscous fan clutch by monitoring coolant temperature,

intake manifold temperature, and air conditioning

status. Based on cooling requirements, the ECM

sends a signal to the viscous fan clutch to increase or

decrease the fan speed.

One thing I'm not entirely clear on is how the ECM signal to the clutch affects a speed change. I assume the voltage signal heats an element inside the clutch which affects a viscosity increase, thereby increasing fan RPM. Does anyone know for sure?



The question is, why is the clutch locked up? Is the check engine light on? If not, then it's probably an issue with the clutch itself, rather than the wiring. But what really needs to happen is someone needs to check the fan clutch control circuitry and be sure it's not shorted on something, causing the clutch to permanently lock. This might be possible if the wiring harness has rubbed through the insulation.



Ideally, someone would take the time to go through and diagnose the problem, rather than throwing parts at it. Unfortunately, if you're not mechanically inclined, you're doomed to whatever dubious advice is dispensed by your mechanic.



Ryan

 

[M Morris]

Ryan,



you are right, the fan clutch is locked up. with the engine off if I try to turn the fan it will only turn when the pulley slips under the belt. When running the fan is fully engaged all the time. if it were electrical would it be locked up running or turned off ? My father looked this up a few weeks ago and said that the bearing is more complicated then your simple off the shelf ball bearing that can be bought for $20, does that sound correct ? I doubt the dealer is trying to screw me on the price of this repair-but then again I did get a good price on the truck and you know the old saying-what you dont get in grapes you make up for in bananas.



Thanks.

 

[rbattelle]

you are right, the fan clutch is locked up. with the engine off if I try to turn the fan it will only turn when the pulley slips under the belt.

Okay, that implies to me that the fan wiring is okay, but the clutch itself has seized up. That means you need a new one, because as far as I know they're not serviceable.



$365 installed doesn't sound too terribly bad...



Ryan

 

[MMeier]

New fan clutch is a shade over $400 around here, bit less if you have connections!: GShail is running the thin line fans in addition to the stock set up, last time I talked to him, I think he was on # 14!!!! I'm on # 4 myself! #@$%! The electric fans are not recommended for any thing over 18k # gross IIRC.

 

[CToney]

I was not impressed with my clutch as I am getting code P4083 for improper fan speed. The flex a lite fan draws a fair bit of juice to make it run. That creates load on the engine. But it might be a good alternative to the stocker if you don't tow heavy. I have one concern. A/C operation at low speeds. The fan should cut in will the Flex a lite do this? One would think that there would be a better clutch out now.

 

[ryecreek]

MMorris

try Ken Diaz at Turbo Auto Diesel in PHX, AZ



4859 W. Van Buren

Phoenix, AZ. 85043

602-272-5311

he builds the B-1 Turbos and does alot of other things including fan/fanclutch work i'd try him he's saved me a ton on all kinds of stuff example rebuilt 2nd gen 24valve rebuilt vacuum pump (5years ago) for $79 when they were non existant mine had a broken ear mopar wanted $1300 try him you may be surprised