The fan is connected thru a viscous coupler to the pulley. This viscous
coupler is liquid filled.
When the liquid is warmed up (higher engine temp, underhood temp, etc) it
becomes thicker
which in turn causes the fan to slip less, which equates to faster fan rpm
and that noise you hear.
You may also notice this on cold startup. This is normal. If you need to
check the coupler,
(with the engine off!!) spin the fan by hand, if the fan will spin more than
5 rotations, replace it.
And yes when it does engage, it will take more power to turn it.
TonyC
-----Original Message-----
From: (MAGNUM S/T) <hoegen@kersur.net>
To: dakota-truck-moderator@bent.twistedbits.net
<dakota-truck-moderator@bent.twistedbits.net>
Date: Saturday, July 28, 2001 8:36 AM
Subject: DML: Stock fan....
>I posted earlier about all the noise my fan was making, but I don't think I
>emphasized the info I was lookin for. I have no doubt the IAT adjuster will
>do wonders and plan on getting it...I'm more interested in the stock fan
>though.
>
>I'd like to know what the heck all the noise is occasionally when I drive.
>It seems that every once in awhile the fan kicks in and in so doing I get a
>loss of HP......is this just my imagination? I know diddly about the stock
>fan's operation, but I had assumed that it is simply belt driven and is
>continuously running, so why do I occasionally get all that "fan" noise as
>if it is kicking into high gear?
>
>...my apologies for my lack of technical abilities
>
>lastly, will an electric fan rid me of these symptoms?
>
>Thanks again
>
>
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