2004 engine fan problem

[gatoraied]

My f250 engine fan seems to rev up wildly but only occasionally. When it does I can hear it in the cab while driving. I thought at first it was the turbo but the other day while having someone hit the pedal I popped the hood and could hear the fan running wild as soon as you gave it some revs. A minute after I started driving all was normal. It's only happened a couple times in the past month, lasts a few minutes then normal. I have 70K on this 6.0. Does this fan operate electronically and with a clutch? Anybody here have this problem
Thanks for your help.

 

[Kleetus]

It is an electro-viscus clutch, so it has a variable lockup rate. Are you sure you're not low on coolant or have a temp sensor going out? It gets its command right from the PCM...

Unless it's physically coming apart, and in that sense, I'd expect you'd be able to rattle it around (with the engine off of course), kinda like a bad water pump bearing.

 

[bigdadie]

My work has a 04 f350 with a plow on it , engine fan seems to rev up occasionally when we drive around with the blade up "this is normal seeing we have air flow blocked some what", is their some thing blocking your air flow? If not, I would check your cooling system!

 

[gatoraied]

I did check the coolant level and it was a bit below the low mark and filled it to the proper level. There was no low coolant idiot light on however. I also checked the fan and it seemed OK as far as bearings etc. it felt tight. As I said it's only happened a couple times and each time for only a few minutes. If it continues I'll have to check the sensor.
Thanks for your input.

 

[bushpilot]

becareful that you dont over fill that degas bottle.

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