New fan clutch never disengage, problem?

[mralaskan]

Hey!

Just installed a new fan clutch (with old fan blade) with the new water pump for my 1500 5.7, 2008, and it sounds like a roaring jet engine all the time. Never disengages, just follows the engines RPM.

Now, I've read all I can find out about this, and gotten different answers, all from "new fan clutch may" be bad to "it's supposed to behave like that". Maybe you all pro's here can give me some input.

The old fan rotated freely by hand and seemed to be working when driving, I never saw it disengage either but it never sounded like this.
Is the new fan clutch just spinning faster somehow? If the old didnt follow the engines rpm?

The sound is roaring and follows the RPM whenever and whereever I'm driving. Gets quieter when cruising at 50 mph and low RPM but whenever I gear down and acc the sound goes up.

The clutch is US MOTOR WORKS MCK1090 from Rockauto

Thanks for any answers.

 

[jws123]

Usually when engine is cold it will roar for first few mins and then quiet down if its staying at 100% all the time then its bad not uncommon for new parts to be bad now.

 

[pacofortacos]

As far as fan clutches go, I only use OEM, they seem to be the only ones that work properly.

Fan should quiet down within the first minute or 2 max on a cold start and shouldn't roar normally - might when taking off from a long red light on a really hot day and hot engine.

They don't disengage to where the ran stops spinning - unless you hold it stopped by hand.

 

[Dean2]

The clutch is defective. Take it back while you still can.

 

[Martins hemi]

Take it back and buy a oem

 

[mralaskan]

Is it possible to return it to ROCKAUTO?
And if buying a new one, how to be sure it wont behave the same.

The clutch can be turned by hand when the engine is off, if I didnt mention that before.

As I said, the fan sounds like it is spinning with the same rpm as the engine, cause when idling its quiet, but every time I accelerate it sounds, and when going past 2-3000 rpm it sounds more than the engine even when on highways. So... isnt the clutch a oil controlled switch? How is it possible to fail, anyone knows?

Thanks

 

[Hemi395]

I agree with everyone here, OEM is the only way to go with a fan clutch.

I believe this is the OEM part you're looking for:

2002-2008 Dodge Fan Drive 52029876AC | All Mopar Parts

2002-2008 Dodge part # 52029876AC - Fan Drive

parts.allmoparparts.com

 

[mralaskan]

Okey, thanks for answers. But still. if there is anyone with info regardin the mechanics of the clutch and how it fails, feel free to comment.

 

[nlambert182]

Fan clutches fail in the engaged position. They never fully disengage so it's normal to see them spin at a slow speed but if it's engaged all the time, the clutch is bad. Send it back and only buy an OEM.

The watered down answer (and my basic understanding) of how they work is that there is a thick silicone type fluid that is held in a reservoir inside the housing. When called upon internal valves open and send the fluid into the working area of the clutch, creating friction that causes the clutch to engage. When the fan is no longer needed, the valves open and the fluid is sent back into the reservoir. There are thermal, non-thermal, and electronic types of fan clutches so how it determines when to open the valves depends on the type. I am not 100% sure which we have.

It can either fail because of a faulty valve, the fluid could leak out, or it could have solidified over time.

 

[Hemi395]

Here's a great video showing how it works:

How Does a Viscous Fan Clutch Work?

Learn what makes a viscous fan clutch operate. Detailed animations show internal components.https://kit-masters.com

youtu.be

 

[mralaskan]

Thanks for the answers! And I will most likely but a new OEM. But...

I temporarily installed the old clutch, which I only replaced because the water pump was replaced, and tried to compare the sounds. They are both THERMAL, with a spring. The outside temperature is 70 degrees when testing.

The old clutch spins freely by hand with some effort (friction) so its not stuck, but it also seems to be spinning at the same rpm regardless of engine acceleration. So with the old clutch there is no excessive noise/sound, you cant hear the fan while driving at all. But it spins...

The new clutch spins freely by hand with some effort also, but after spinning it for a while by hand it becomes close to zero friction and spins multiple revolutions just by one spin by hand. This clutch follows the engines rmp at all times, no matter the load or speed. So the fan oversounds the engine when driving on highways.

So, which one is actually bad? Maybe both?

 

[nlambert182]

They always spin to some degree. That in itself doesn't make it bad. But it should more closely match engine rpms when it engages. You should be able to hear it engage (primarily a big whoosh of air as it spins up) So if it the old fan always rotates at the exact same speed and never ramps up to match the engine rpm, then it "might" not be engaging. If the new one always matches engine RPMS and never slows down then it "might" be stuck in the engaged position.

It's difficult to determine if either are bad but I would lean towards the new one possibly being bad and the old one likely doing what it's supposed to do. Install it and run it for a while to see if you can hear it engage.

 

[mralaskan]

Yes, I thought that might be the case. So I guess I have one that never engages and one the never disengages!...

 

[nlambert182]

Well "maybe".... Maybe not. If the old fan wasn't giving you problems when you changed it, stick it back on and drive it for a bit. Really get it up to operating temp to see if you can hear it engage. If I'm on the interstate doing 70 mph my coolant temp will creep up to 217 before the thermostat opens and the fan engages. As soon as it does the temp drops back to just under 200 in a few seconds. Inside the truck the fan is not really audible, but if I stop it in the driveway to idle and get out just before the temps get up there, they will creep on up and the fan is audible when it engages. Might be worth a shot.

On my Cummins it was really audible. When the fan engaged you could hear it over the radio and the coolant temp would drop back down to 185. You could actually feel it pull on the motor.

 

[mralaskan]

Thanks, yes i have installed the old clutch and will test if.
But with your cummins, when the sound was so loud, was it normal? Supposed to be?

 

[Sherman Bird]

Hey!

Just installed a new fan clutch (with old fan blade) with the new water pump for my 1500 5.7, 2008, and it sounds like a roaring jet engine all the time. Never disengages, just follows the engines RPM.

Now, I've read all I can find out about this, and gotten different answers, all from "new fan clutch may" be bad to "it's supposed to behave like that". Maybe you all pro's here can give me some input.

The old fan rotated freely by hand and seemed to be working when driving, I never saw it disengage either but it never sounded like this.
Is the new fan clutch just spinning faster somehow? If the old didnt follow the engines rpm?

The sound is roaring and follows the RPM whenever and whereever I'm driving. Gets quieter when cruising at 50 mph and low RPM but whenever I gear down and acc the sound goes up.

The clutch is US MOTOR WORKS MCK1090 from Rockauto

Thanks for any answers.

Aftermarket is the likely problem.

 

[Meji]

Just return it and purchase an OEM

 

[nlambert182]

Thanks, yes i have installed the old clutch and will test if.
But with your cummins, when the sound was so loud, was it normal? Supposed to be?

Yes. The fan was doing it's job. As soon as the engine cooled back down the fan disengaged. It's a big fan and had to move a lot of air.

 

[Ckidd_21]

Curious if you saw a drop in MPG? I noticed the loud roaring noise and am pretty sure it’s a bad fan clutch. Since noticing it I’ve seen about 1 MPG drop and was curious if a bad fan clutch leads to this?

 

[mralaskan]

Didn't notice. But if anything it would be an increase of MPG if the fan's constant high rpm actually taking more power out of the engine.