Fan clutch versus electric fans

External Since: Jul 25, 2005 Posts: 7

I have an 03 silverado, 4.8 V8( just got the 36, ooo mile service done
by the way) I drive in hot weather (100-115) very frequently, and
notice if I'm in traffic and with the a/c on very low ( dial 1-2) the
engine starts to heat up ,I know its kind of normal, but it heats up
very quickly, which brings me to wonder why other cars beside me can go
on driving like nothing, for an example, a 04/05 ford f-150 truck was
beside me and dude was comfortable with his a/c on, mean while I had to
turn my windows down and submit to the heat and the ford , so I figure
since my truck has a fan clutch and not electric fans(which seem to
work better in hot traffic), if it is possible for me to put some
electric fans on my truck and if so is it very diffulcult to do so and
are they any risk of ruining my warranty(extended), but considering
that the new 05/06 silverado/sierras have them, so getting them I think
wont be a problem

External Since: Nov 28, 2004 Posts: 106

Our 98 Tahoe 6.5TD has the stock serpentine belt driven
clutch with HD 20" metal fan blades that is rated to move
over 10,000 or so cfm. Worked fine during these just past
hot Northeast summer days.

I've been searching for a dual electric fan/shroud setup but
the max I can find (if the spec is advertised at all) is
only 7,000 cfm. Will 3,000 cfm make a difference? I think
so because of the a/c condenser, engine oil cooler and
tranny oil cooler sitting in front of the radiator.

Some clutch/fan blade setups work poorly during idling
conditions (stop and go traffic) causing engines to overheat
or come close to it. Other setups work well during idling
conditions (like ours) but at the expense of fuel
efficiency. You may want to consider extreme duty
clutch/fan setups that use very aggressive metal blades.

You should also check your fan shroud to make sure there is
little or no "leakage" -- you want the fan blades to draw in
air through the radiator and not into holes or gaps behind
the radiator. How much clearance betweent the blades and
the shroud? You may want to consider a larger diameter fan
blade but also consider the pitching motion of the engine --
the blade may scrape the shroud. Make sure that no more
than half of the blade's cross-section is outside the
shroud.

Good luck. Franko

"jmex" <chevy350ss RemoveThis @hotmail.com> wrote in message
news:1126113881.144522.219530@g14g2000cwa.googlegroups.com...
> I have an 03 silverado, 4.8 V8( just got the 36, ooo mile
service done
> by the way) I drive in hot weather (100-115) very
frequently, and
> notice if I'm in traffic and with the a/c on very low (
dial 1-2) the
> engine starts to heat up ,I know its kind of normal, but
it heats up
> very quickly, which brings me to wonder why other cars
beside me can go
> on driving like nothing, for an example, a 04/05 ford
f-150 truck was
> beside me and dude was comfortable with his a/c on, mean
while I had to
> turn my windows down and submit to the heat and the ford ,
so I figure
> since my truck has a fan clutch and not electric
fans(which seem to
> work better in hot traffic), if it is possible for me to
put some
> electric fans on my truck and if so is it very diffulcult
to do so and
> are they any risk of ruining my warranty(extended), but
considering
> that the new 05/06 silverado/sierras have them, so getting
them I think
> wont be a problem
>

Joined: May 17, 2005 Posts: 1396

Actually you will find that it can move a lot more than 10,000 CFM at max effort with it likely peaking out at between 20 and 30 thousand CFM with a good engine driven fan and beable to handle a bit of backpressure too. Electric fans are power limited in a car the to deleiver a true 10,000 CFM plus with the restrictions in the core path and backpressure in engine compartment (those electric are rated in free air not installed) it would tkae atleast 150 to 200 amps or more to power the motor and your trucks electric system cannot handle that kind of load and that is why they do no exist in the after market. 40 amps or so is the cut off for electrically drive fans and you can only move so much air with that amount of current on 12 volts.
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