Failed Fan Clutch, I think.

[Tuesdak]

Get a MOPAR clutch not aftermarket: maybe it works maybe it doesn’t work so well… Was it the problem or not being unanswered.

Fans are a load that by design tighten the nut. Turn the nut in the direction the fan spins to loosen it. They fall off when engine is stopping BFD. It would be a BFD if they loosened up and come off at full RPM!

 

[Loren]

Thanks again to all who offered opinions and help.

I finally got the fan clutch changed today. Based on several things I've read I got a genuine MOPAR clutch from Geno's Garage.

I also ordered the wrench set that's supposed to make getting the clutch unscrewed easier. The wrench set helped, but still leaves a lot to be desired. First, and most important, the handle on the wrench isn't long enough. I had to find and cut a piece of pipe to get enough leverage to loosen the nut.

The other issue is with the tool that's used to hold the pulley and prevent it from turning. It's supposed to be used with a 3/8" breaker bar or similar tool. It sits over three bolts on the pulley and it took me about twenty or thirty tries before I got it to stay in place. I also had to use a piece of pipe on it because the breaker bar flopped around too much and also wasn't long enough.

If I have to do this job again I'll weld or bolt handle extensions on both of those tools.

Once I got the fan clutch off the shaft I tried to pull it out without removing the fan shroud, but that didn't work. I removed the four nuts holding the fan shroud in place and managed to push it up with the fan inside until the fan cleared it enough to pull out. I didn't have to pull the shroud all the way out.

Everything went back together as expected and I coated the nut's threads with anti-seize before putting the new fan clutch on. Getting the threads started was a big pain, but I finally got it done.

The whole job took three and a half hours. It should have been a one hour job. Now that I know what's involved it will go a lot faster the next time.

I still don't know for sure if the fan clutch was actually the problem. I won't be able to do an actual test until I pull the trailer again. I have a trip planned coming up in about a week so I should know then. I'll update here after that.

Thanks again,
-- Loren

 

[Ltngdrvr]

Well, it better be the clutch, or it will be a very expensive way to find out it wasn't!

 

[petersonj]

The wrench set helped, but still leaves a lot to be desired. First, and most important, the handle on the wrench isn't long enough. I had to find and cut a piece of pipe to get enough leverage to loosen the nut.

The other issue is with the tool that's used to hold the pulley and prevent it from turning. It's supposed to be used with a 3/8" breaker bar or similar tool. It sits over three bolts on the pulley and it took me about twenty or thirty tries before I got it to stay in place. I also had to use a piece of pipe on it because the breaker bar flopped around too much and also wasn't long enough.

It's hard to believe that someone designing fan clutch tools would design them the way they did. Connect a ratchet to the tool where you can't reach? a handle so short that you cannot get any leverage? I suffered the same fate, so I modified mine. They are now very effective tools and easy to use. Note the added 19 mm / 3/4" bolt heads I welded on for easy extension for more leverage

- John

.

 

[Tuesdak]

I use "real tools" for the job. Had to remove two of the 8MM bolts. One wack and it was loose.

 

[Loren]

Well, it better be the clutch, or it will be a very expensive way to find out it wasn't!

You got that right!

-- Loren

 

[Loren]

I tried the "whack" method and all I did was make it mad. An air hammer on the wrench didn't work either, although it did dimple the end of the wrench. It wasn't until I stuck some pipes on the wrenches that I got enough leverage to break the nut loose.

John, I don't think I'll modify my wrenches the same way you did. I'm thinking that I'll get some steel and bolt handle extensions onto the wrenches. That would allow me to shorten the wrenches to fit them into a toolbox. With luck it will be a long time before I need to do this again. I hope I haven't forgotten how by then.

Thanks for the suggestions.

-- Loren

 

[Tuesdak]

An air hammer on the wrench didn't work eithe

FWIW the air hammer goes direct on the fan clutch nut to loosen it. It works very well.

 

[Loren]

I finally towed the trailer again. Changing the fan clutch had no affect on the temperatures. From this I conclude that either:
1. The fan clutch is not the problem and there is a different problem.
or
2. The system is behaving normally and that I have just not noticed the high temperatures that I am seeing now. My truck now has 80,000 miles so it's unlikely that I have overlooked high temperatures for so many miles.

I'm leaning towards #2, but I can't believe that these temperatures have always been this high and I just never noticed it. I do hear the fan occasionally, but not often, and it never reaches full speed to where it roars. Actually, my old fan clutch did the same thing.

In a few days I'll have occasion to pull our heavy trailer up the steep half-mile hill and if the fan clutch doesn't roar by the time I get to the top I'll know that something is wrong.

Pulling the trailer on mostly flat roads I saw the coolant temperature sometimes reach 220-225 degrees. In the past it has been pretty stable at about 190 and if it got much higher than that I would hear the fan turning.

I'll know more after I drive up that hill. If I still suspect a problem I may wind up at the dealer.

Thanks again to all who helped out.

-- Loren

 

[AH64ID]

We towed around 20K GCW this last weekend with constant temps in the 90-100°F range. Fan is always enhanced above 215°. ECT got as high at 221°, highest I’ve seen yet, and the fan was always noticeable.

I did find that I used ERS and stayed in lower gears on LONG slow pulls the ECT would stay much lower and fan rpms stayed in the 1500-2200 rpm range.

Ive seen fan rpms over 2800 but never with crazy ECT so I think it must have to do more with a combo of ECT and A/C pressure.

 

[Ltngdrvr]

Anything over 217 and you should be hearing that fan at full engagement.
It needs to be driven at those high temps with the dealer level scan tool hooked up so all sensor outputs and fan outputs can be viewed.

 

[Loren]

We towed around 20K GCW this last weekend with constant temps in the 90-100°F range. Fan is always enhanced above 215°. ECT got as high at 221°, highest I’ve seen yet, and the fan was always noticeable.

I did find that I used ERS and stayed in lower gears on LONG slow pulls the ECT would stay much lower and fan rpms stayed in the 1500-2200 rpm range.

Ive seen fan rpms over 2800 but never with crazy ECT so I think it must have to do more with a combo of ECT and A/C pressure.

AH64ID,

What's ERS? What's ECT?

I appreciate the help, but I don't understand it.

-- Loren

 

[Loren]

Anything over 217 and you should be hearing that fan at full engagement.
It needs to be driven at those high temps with the dealer level scan tool hooked up so all sensor outputs and fan outputs can be viewed.

Ltngdrvr,

That has always been my experience (with the fan engagement) too. I guess I'll be seeing the dealer to see what's wrong.

Apparently it's not the fan clutch. That's too bad because that was something I could do myself for a reasonable price. I'm sure a trip to the dealer will be much more expensive.

Thanks,
-- Loren

 

[AH64ID]

AH64ID,

What's ERS? What's ECT?

I appreciate the help, but I don't understand it.

-- Loren

ERS: Electronic Range Select. The ± on the steering column.
ECT: Engine Coolant Temperature.

 

[bcbender]

yeah, I was in the 215-217 range pulling hills out in WY a few weeks ago... but dropped quickly once the load reduced on the dh. The AISIN on the other hand only ever went from 165 to 167 and that was only on the hwy 14 grade going to Cody from Sheridan.

 

[Loren]

In a few days I'll have occasion to pull our heavy trailer up the steep half-mile hill and if the fan clutch doesn't roar by the time I get to the top I'll know that something is wrong.

-- Loren

I finally pulled the trailer up the steep hill. By the time I got to the top the fan was turning at engine rpm or something very close to it.

The fan engaged at a coolant temperature of about 205 degrees and rpm increased as temperature increased as I continued up the hill.

I now think that the fan clutch may have fixed the problem. I'm going to leave things alone for now and see if I have problems later. I'm keeping my fingers crossed.

Again, thanks to all who helped.

-- Loren

 

[cricha]

im having some of the same problems. pulled tstat and compared how far it opened to a new tstat. old one was only opening half way. that was part of the problem. now just trying to get the fan clutch out to replace the fan clutch. fan clutch was maxing out rpm at about 1625. getting the shrouds off is where im at right now

 

[Loren]

I'm still not seeing the temperatures I expect to see so I ordered a new thermostat from Geno's Garage. It should be here in a day or so. I'm hoping that it will help bring my temperatures back down to normal levels.

 

[Loren]

... getting the shrouds off is where im at right now

cricha,
I didn't have to remove the shrouds to change my fan clutch. I did remove the 4 bolts (or maybe they were nuts - I can't remember) holding the fan shroud. This allowed me to scoot the fan clutch up together with the shroud until I got the shroud about halfway up. At that point there was enough clearance to get the fan clutch out with the fan attached.

Good luck.
-- Loren

 

[AH64ID]

I'm still not seeing the temperatures I expect to see so I ordered a new thermostat from Geno's Garage. It should be here in a day or so. I'm hoping that it will help bring my temperatures back down to normal levels.

What are you seeing?