Need advice. Have a engine flex fan, going to electric

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jobguy

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Mar 19, 2005
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Minnesota
I switched from the original engine cooling fan which did not work very well a to a flex fan which runs whenever the engine is running. The fan blades flex and thus push less air as engine speed increases. Does a fantastic (pun intended) job cooling the engine. BUT..... the fan makes so much noise you can forget conversation at highway speeds. I tried several different spacers and did get the noise below jet turbine level. Have any of you gone to an electric fan with no engine driven fan? If so are you satisifyed with the result?
 

Phil

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Mar 5, 2005
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982
jobguy said:
the fan makes so much noise you can forget conversation at highway speeds.

It's hard to move a lot of air without some noise.  I once had a motorhome with a temperature controlled clutch that would run at slow speed most of the time.  That was great because the fan noise came on only with very high outside temperatures.  You had to stop chatting if you were pulling a long hill with 100F outside.  ;D

I finally solved the fan noise problem for good by replacing the motorhome with a rear engine diesel.

Phil

 

Karl

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Mar 3, 2005
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Elkhart Lake, WI for the summer. Work at Road Amer
There are those of us who can't afford to replace the fan with a $$$$$$$ diesel pusher :-\ Your original fan was probably a viscous clutch fan which does a good job of maintaining a relatively constant engine temp. at all speeds and ambient temp's. It's possible that some fluid has leaked out or the thermostatic spring that controls fan speed has gone weak or has broken. Check it out carefully before going to electric fans, which would involve quite a bit of work to get the shrouding installed properly. Usually there's precious little room for a mod. of that type.
 

Gary RV_Wizard

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Feb 2, 2005
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At our Silver Springs FL home
My motorhome has (stock) two electric fans in addition to the engine-driven fan. The electrics are variable speed and thermostat-controlled, so they only cut in when the engine fan is no longer keeping up with cooling demand. Still, when they do cut in the additional air flow is very noisy. 

The noise is not particularly because of the electric motor, though there is a bit of motor whine that bothers some people more than others.  It's the tremendous rush of air.
 

Karl

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Elkhart Lake, WI for the summer. Work at Road Amer
You're lucky, Gary, to have them already there. I've seen people retrofit them to gain a few more horsepower (actually use less horsepower) with near disaterous results if done incorrectly. The flex fans are inherently noisy, but fitting a larger diameter drive pulley will quiet them somewhat by driving them slower, but you have to make sure you have adequate airflow at the slower speed. Of course that would also require a different length drive belt.
 

ffruff22

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Joined
Apr 5, 2005
Posts
11
Location
MICHIGAN
I have a modified jeep wrangler (chevy 350, T5, 4.10's,etc) that I have used all of the above in at one point or another.  I initially started out with the Chevy clutch fan after a year or so, on of the blades decided to seperate itself from the rest of the fan, so I switched to the flex-fan.  It sounds neat at first, but it gets old real quick.  Aside from the noise, if you do a lot of highway driving it takes away power (the clutch fan and electric usually freewheel when at speed because you are forcing the air thru the rad by driving).  I installed an electric fan that worked great to solve this and it would suck a piece of paper to the grill from a foot away. 
I eventually put in a Be Cool aluminum radiator and replaced the electric fan with another clutch fan and havent had any problems. 
 

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