Surging fan clutch

[mfurrh55]

Does this sound normal, I changed out fan clutch with aftermarket one lifetime warranty. , but I can be driving with AC on high and I can hear fan clutch kicking in then out and so on, pick up some speed it either goes away or stays on not surging, I didn't get this with original one, I never got any codes on old fan clutch either, I changed it because it wouldn't cool idling, fan wouldn't come on either, any thoughts? TIA, Monte

 

[Wayne M.]

Hi Monte,
Exactly which brand clutch is it? Many of us haven’t had luck with aftermarket units. I replaced mine with a Mopar unit, and as when it was new, I only hear a bit of roar when I’m idling hot with the ac on and I raise engine speed.
I replaced mine because a wire rotted out, and I too thought the low speed clutching was going away, and I was having poor ac condenser cooling.

 

[mfurrh55]

I got it from AutoZone, put it on back in January, I noticed it kicked in right after starting truck, and still does, but it's the surging that I can't figure out, especially around 35 mph, I guess I need to turn ac off and see if it changes ,at least my ac stays cool idling now, oh well, I just don't like it running all the time, on a long trip it will affect my mpg, don't want that, Thanks, Monte

 

[Prairie Dog]

No, it shouldn't surge like that at 35 but that's probably just the way it is. The aftermarket just cant seem to get them straight.
I can almost guarantee you will end up with an OEM unit.

 

[mfurrh55]

No, it shouldn't surge like that at 35 but that's probably just the way it is. The aftermarket just cant seem to get them straight.
I can almost guarantee you will end up with an OEM unit.

Thanks, I will get one when funds are available,my wife had surgery back in June and everybody and their brother has their hand out wanting money, my savings account dwindled pretty quick, guess I'll have to put up with the surging for a while longer,Monte

 

[AH64ID]

It sounds like normal fan commands are coming from the ECM, but the aftermarket unit doesn’t vary clutch engagement like the OEM one does. So it’s more of an on/off fan than it used to be.

 

[Ozymandias]

That would set a code as there are command and return values from the ECM to the Clutch and back.

Just fording a 3' river made my truck set a code a go into limp from this as the water slowed down the Fan.

 

[AH64ID]

Yes slow fans will set a code, but I pretty sure too fast won’t... which is what the OP seems to be describing.

 

[mfurrh55]

It's more like it's kicking in, then kicking out,and so on,that's what I mean by surging

 

[AH64ID]

It's more like it's kicking in, then kicking out,and so on,that's what I mean by surging

They are pulse width modulated, so that sounds correct. The clutch likely isn't as smooth in the cheaper clutches.

 

[mfurrh55]

They are pulse width modulated, so that sounds correct. The clutch likely isn't as smooth in the cheaper clutches.

Oh, ok Thanks for responses, didn't know if I had something that was gonna leave me stranded somewhere,I guess you get what you pay for, I paid 120.00 with lifetime warranty, I did have to change out the bracket on wire with the original one because when I turned the fan it would hit the wire, put original bracket in place of one that came on it and no problem with clearance, Thanks again, Monte

 

[Ozymandias]

There is nothing like kicking in or out, this clutch speeds up the fan smoothly to the desired speed that the ECM wants to see, and also fades out smoothly when the ECM says so.
Anyways without a trailer you should almost never hear the Fan, i can't remember when i heard mine the last time, not even the Independence Pass was hard enough on the engine to let it use the Fan.

 

[AH64ID]

View attachment 115351 There is nothing like kicking in or out, this clutch speeds up the fan smoothly to the desired speed that the ECM wants to see, and also fades out smoothly when the ECM says so.
Anyways without a trailer you should almost never hear the Fan, i can't remember when i heard mine the last time, not even the Independence Pass was hard enough on the engine to let it use the Fan.

Yeah, it should be smooth but I am guessing the cheaper clutches aren't OEM smooth.

 

[Prairie Dog]

Doubt there's any command to engage at 35 mph. I suspect it's just this particular clutch responding to the extra heat that's coming through the rad. because of the AC being on.
Remember, these are Electric and Thermal.

 

[cerberusiam]

If you just hear and not feel the fan come on and off it is not a problem. The 6.7 fans work like that, you will hear them spool up and down all the time driving.

 

[mfurrh55]

If you just hear and not feel the fan come on and off it is not a problem. The 6.7 fans work like that, you will hear them spool up and down all the time driving.

That's what seems like what is happening, when it comes on I don't feel it do anything to engine, just makes roaring sound, then quits, then comes back etc..., Thanks for replies, Monte

 

[AH64ID]

Doubt there's any command to engage at 35 mph. I suspect it's just this particular clutch responding to the extra heat that's coming through the rad. because of the AC being on.
Remember, these are Electric and Thermal.

That’s the first I’ve heard they have any thermal properties. I monitored fan rpms on my 05 and never saw it engage any different than the programmed settings. There are a lot of variables into fan engagement.

They do have slow speed AC setting... among many others.

 

[AH64ID]

If you just hear and not feel the fan come on and off it is not a problem. The 6.7 fans work like that, you will hear them spool up and down all the time driving.

All the time. The slower you go, with the AC on, the more you hear it.

I had reprogrammed my 05’s fan and it cycled more. Before I reprogrammed it I had never heard it. After reprogramming my ECT never topped 211 (vs 217), and my AC worked much better below 45.

 

[sojoe]

did you get a code PO483 prior to installation of new aftermarket fan clutch?
Do you get any DTC`s now?

 

[mfurrh55]

did you get a code PO483 prior to installation of new aftermarket fan clutch?
Do you get any DTC`s now?

No never got any codes prior or afterward, decided I'd check fan clutch after I was getting warm air idling, and it wasn't kicking on