# 2000 Navigator fan clutch question



## Oso954 (Jun 23, 2012)

Replace it.


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## Bigplanz (Apr 10, 2009)

Oso954 said:


> Replace it.


I just looked in my Haynes manual and it said on a cold engine, it should spin freely, hot engine, some resistance should be felt. It has been like this for at least 35K miles.

Yay, another job to keep me busy in retirement!


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## ukrkoz (Dec 31, 2010)




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## Bigplanz (Apr 10, 2009)

ukrkoz said:


> https://www.youtube.com/watch?v=cOXcrbQRDWU


I saw this video a few days ago but his situation involves a clutch that doesn't engage at all, resulting in overheating. Mine is permenantly engaged resulting in a loud fan, poor gas mileage, and underheating.


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## de-nagorg (Feb 23, 2014)

Another noise you might be experiencing.

Ford power Steering pumps are notorious for a howling whine, when they get a few thousand miles on them. 

Seen it many times.


ED


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## ukrkoz (Dec 31, 2010)

I understand, Big. I have question though. Do you know it engaged all the time? Every truck I had, including new one and my 98 MGM, they all have fan spinning along with engine rotation. They all sound like tanks, really. Kinda like it. 

So it is just rotating at few hundred RPM, as it should, or it is going all the time full speed? 

A large V8 is a large V8. They are loud, fan or not.


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## Bigplanz (Apr 10, 2009)

ukrkoz said:


> I understand, Big. I have question though. Do you know it engaged all the time? Every truck I had, including new one and my 98 MGM, they all have fan spinning along with engine rotation. They all sound like tanks, really. Kinda like it.
> 
> So it is just rotating at few hundred RPM, as it should, or it is going all the time full speed?
> 
> A large V8 is a large V8. They are loud, fan or not.


From what I have read on-line, the fan clutch varies the speed of the fan relative to both engine temperature and RPM. The little clock spring that opens and closes the valve to regulate the silicone fluid will open the valve fully when the engine is hot at high RPM, for maximum cooling, then, close slightly and lower the fan speed (even with the engine fully hot) at lower RPM. The fan RPM is limited to a max value, so it doesn't follow engine RPM

All this is calibrated to help keep the engine coolant at the proper temp (195-205). My engine is never hotter than 190, and usually around 185-188. The fan is "always" on, in other words. If the clutch fails the other way, the fan just free wheels and the engine overheats at idle and the AC doesn't work right. 

Since mine is stuck open, the truck runs fine, just at lower temp and with a loud fan. Presumably, with worse gas mileage as well, but, well, who gets great gas mileage with an old Navigator anyway?

The fan (as shown in the video) is very hard to turn on a cold engine. Service manual says it should turn freely while cold. That leads me to conclude that the clutch is always engaged.


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## iamrfixit (Jan 30, 2011)

On the 6.8 V10 in my F250, the fan is pretty hard to turn when the engine is cold. Every morning it always roars when the engine is first started and when I take off for the first time. After that first launch I hear and feel the change when the fan cuts out. It takes a bunch of horsepower to spin the fan and it's loud when fully locked up. 

I can hear the fan engage and disengage occasionally, like when idling on a hot day. I don't think it ever engages fully like it is when the truck is started the first time in the morning. I've never seen the temp gauge even running the slightest bit warm. I've pulled heavy loads on hot days, lots of idling with the AC running, nothing seems to heat it up even the slightest. I definitely never hear the fan roar like it does on that first start.


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## Bigplanz (Apr 10, 2009)

iamrfixit said:


> On the 6.8 V10 in my F250, the fan is pretty hard to turn when the engine is cold. Every morning it always roars when the engine is first started and when I take off for the first time. After that first launch I hear and feel the change when the fan cuts out. It takes a bunch of horsepower to spin the fan and it's loud when fully locked up.
> 
> I can hear the fan engage and disengage occasionally, like when idling on a hot day. I don't think it ever engages fully like it is when the truck is started the first time in the morning. I've never seen the temp gauge even running the slightest bit warm. I've pulled heavy loads on hot days, lots of idling with the AC running, nothing seems to heat it up even the slightest. I definitely never hear the fan roar like it does on that first start.


Is your the older design, or the current electronically activated fan clutch?


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## ukrkoz (Dec 31, 2010)

iamrfixit said:


> On the 6.8 V10 in my F250, the fan is pretty hard to turn when the engine is cold. Every morning it always roars when the engine is first started and when I take off for the first time. After that first launch I hear and feel the change when the fan cuts out. It takes a bunch of horsepower to spin the fan and it's loud when fully locked up.
> 
> I can hear the fan engage and disengage occasionally, like when idling on a hot day. I don't think it ever engages fully like it is when the truck is started the first time in the morning. I've never seen the temp gauge even running the slightest bit warm. I've pulled heavy loads on hot days, lots of idling with the AC running, nothing seems to heat it up even the slightest. I definitely never hear the fan roar like it does on that first start.



Same here, both on 2019 Dodge RAM and 98 MGM with Ford 4.6L V8. 

This is why I ask - are you sure it's brok?


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## Bigplanz (Apr 10, 2009)

ukrkoz said:


> Same here, both on 2019 Dodge RAM and 98 MGM with Ford 4.6L V8.
> 
> This is why I ask - are you sure it's brok?


All I know is what the manual says. "Should turn freely when cold." It doesn't. Probably not a big deal, though since it has been this way since I got the Navigator 35K miles ago. Glad I finally replaced the other bsd rear trailing arm. That was definitely broke!


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## iamrfixit (Jan 30, 2011)

Bigplanz said:


> Is your the older design, or the current electronically activated fan clutch?



It's a 2000 so no electronics on the fan clutch


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## Bigplanz (Apr 10, 2009)

Here are the temperature readings after a 20 mile (mostly interstate) drive this morning. 181.4 coolant temp is pretty low. Radings taken at idle.


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## Bigplanz (Apr 10, 2009)

For comparison with the first video, here is the fan clutch resistance with the engine fully hot. There is some difference, but not much.


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## carmusic (Oct 11, 2011)

maybe your fan clutch is bad, but i would check your thermostat also, i already had one that had stuck opened so temp was always lower than normal


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## Bigplanz (Apr 10, 2009)

carmusic said:


> maybe your fan clutch is bad, but i would check your thermostat also, i already had one that had stuck opened so temp was always lower than normal


When I got the truck 3 years ago, I noticed the low engine coolant temp and replaced the T stat with a Stant. No difference. Just recently occurred to me that the fan clutch could be the culprit.


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## de-nagorg (Feb 23, 2014)

Bigplanz said:


> When I got the truck 3 years ago, I noticed the low engine coolant temp and replaced the T stat with a Stant. No difference. Just recently occurred to me that the fan clutch could be the culprit.


What temp rating did you install?

Should be operating at or very near the rating that you installed.


ED


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## ukrkoz (Dec 31, 2010)

Big, you may also consider high temp t-stat. But those large engines they simply do not heat up too much. My 4.6LV8 sits at the below mid on temp dial all the time. And everything works as it should. 

But boy, I took my RAm to work today and is that thing LOUD after start up!! Love it! Damn raw power...


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> What temp rating did you install?
> 
> Should be operating at or very near the rating that you installed.
> 
> ...


195 degrees.


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## ukrkoz (Dec 31, 2010)

Soooo... you are 7 degrees off? And you are worried? Place piece of cardboard in front of radiator, to cover maybe half of it.


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## Bigplanz (Apr 10, 2009)

ukrkoz said:


> Soooo... you are 7 degrees off? And you are worried? Place piece of cardboard in front of radiator, to cover maybe half of it.


No, not worried, just curious. I have driven it 35K miles this way, and it runs great, just a little cold. Our Windstar has a 195 T stat and is always around 200 for coolant temp. I have always heard an engine should run at the right temp to keep the combustion by products down and make sure the heater works right.

If I replace it, it will be because I need something to keep me busy.

Oh, and from the screenshot I posted, it is about 14 degrees off. Seems like a lot considering I had just gotten off the interstate.


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## de-nagorg (Feb 23, 2014)

ukrkoz said:


> Soooo... you are 7 degrees off? And you are worried? Place piece of cardboard in front of radiator, to cover maybe half of it.


I have did that on an older Big Block F250, works great in winter, but remember to remove it in the summer, or you will overheat fast.


ED


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## ukrkoz (Dec 31, 2010)

Nope. If you have clean open cooling system, it will work just fine. Back in ol country, we had OEM metal shades in front of radiators, folks drove with them shut or partially open year long.
MOF, I had CR-V engine fully wrapped in insulation blanket, when I experimented with HAI vs CAI. 100 degrees outside, no problem.


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## ukrkoz (Dec 31, 2010)

Bigplanz said:


> No, not worried, just curious. I have driven it 35K miles this way, and it runs great, just a little cold. Our Windstar has a 195 T stat and is always around 200 for coolant temp. I have always heard an engine should run at the right temp to keep the combustion by products down and make sure the heater works right.
> 
> If I replace it, it will be because I need something to keep me busy.
> 
> Oh, and from the screenshot I posted, it is about 14 degrees off. Seems like a lot considering I had just gotten off the interstate.


 Hotter engine burns better. Hot t-stats are performance items. Not engine pulverizes gasoline better as it come spre heated.


Otherwise, as they say in the great state of TN, don't fix if it ain't brok, if it's brok, fix right away.


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## Bigplanz (Apr 10, 2009)

Since the Nav runs great, this issue is low on the priority list. Need to change the differential fluid next. Rear brakes need pads and rotors too. I don't fix stuff unless it is broke.


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