Clutch fan vs electric fan
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: Clutch fan vs electric fan
The viscous clutch is filled with silicone fluid
that will leak out slowly if the clutch is not stored
in the same position as it is on the engine.
Before spending a lot of money on electric fans
it is still a good idea to do a test with and without
your fan blades during cooler winter weather to see
how much you can actually save.
The best test is with two trucks following one another on a trip.
Do the trip with both trucks using the factory fan.
Then do a second trip with the fan off your truck,
but your buddy's truck still with its fan as a 'control'.
For the greatest certainty and accuracy, do a third trip
where you put your fan back on as the 'control'
and your buddy's truck takes the fan off.
Don't believe any manufacturer's advertising about what their electric
fan CFM is. They don't test it on your truck radiator and shround which is
ALL IMPORTANT. There is a lot of lying and trickery about electric fan
CFM...just ignore it.
Just buy the electric fan that pulls the most amps that your present alternator can generate. Don't forget alternator capacity when thinking about electric fan conversions. In rough numbers 60 amps is about a horsepower of fan capacity.
Think about a conversion that still allows you to put your viscous fan back on easily if you tow. There is no electric fan available that can supply the 12 horsepower of fan capacity that the mechanical fan puts out at 4,000 rpm. This is only important when towing heavy trailers up steep interstate hills at 45 mph or less, especially at altitudes above 5000 feet.
that will leak out slowly if the clutch is not stored
in the same position as it is on the engine.
Before spending a lot of money on electric fans
it is still a good idea to do a test with and without
your fan blades during cooler winter weather to see
how much you can actually save.
The best test is with two trucks following one another on a trip.
Do the trip with both trucks using the factory fan.
Then do a second trip with the fan off your truck,
but your buddy's truck still with its fan as a 'control'.
For the greatest certainty and accuracy, do a third trip
where you put your fan back on as the 'control'
and your buddy's truck takes the fan off.
Don't believe any manufacturer's advertising about what their electric
fan CFM is. They don't test it on your truck radiator and shround which is
ALL IMPORTANT. There is a lot of lying and trickery about electric fan
CFM...just ignore it.
Just buy the electric fan that pulls the most amps that your present alternator can generate. Don't forget alternator capacity when thinking about electric fan conversions. In rough numbers 60 amps is about a horsepower of fan capacity.
Think about a conversion that still allows you to put your viscous fan back on easily if you tow. There is no electric fan available that can supply the 12 horsepower of fan capacity that the mechanical fan puts out at 4,000 rpm. This is only important when towing heavy trailers up steep interstate hills at 45 mph or less, especially at altitudes above 5000 feet.
RE: Clutch fan vs electric fan
ORIGINAL: JJ67RS
Hey Just a little tid bit of info... yeah the fan clutches are filled with a type of oil, but their function is less about the oil inside of them as it is about the BI-metalic spring. I am not an engineer, but basically it has to do with expansion and contraction rates of the metals that make up that spring from the changes in temp, that controls how the fan spins. In my Opinion, I think you guys would be better off leaving the factory setup the way it is.. And the guy whose fiance has trouble getting hers warm, I would flush that cooling system, and check the radiator for clogs with one of those laser thermometers for hot and cold spots, there must be a clog somewhere. I understand it is cold where you live, I am in Rhode Island...and we have had many single digit days the last several winters with wind chills dipping well below 0, and I have had no problems with heat. But If you all are really out to save gas I would suggest checking out 4 things, cheapest being tire air pressure, check it regularly...#2 switch to a good full synthetic oil, i like Mobil 1, noticed a big difference, dont know exact % though...and #3 look at the type of tires you are using, if you are using aggressive soft compound tires youll never get good mileage, need a street tire... rolling resistance kills mpg's, and lastly #4 if you have exhaust leaks up front, its gonna mess with your 02 sensors creating a lean condition and causing the computer to put more fuel into the mix... well Hope this helped good luck... Jay
Hey Just a little tid bit of info... yeah the fan clutches are filled with a type of oil, but their function is less about the oil inside of them as it is about the BI-metalic spring. I am not an engineer, but basically it has to do with expansion and contraction rates of the metals that make up that spring from the changes in temp, that controls how the fan spins. In my Opinion, I think you guys would be better off leaving the factory setup the way it is.. And the guy whose fiance has trouble getting hers warm, I would flush that cooling system, and check the radiator for clogs with one of those laser thermometers for hot and cold spots, there must be a clog somewhere. I understand it is cold where you live, I am in Rhode Island...and we have had many single digit days the last several winters with wind chills dipping well below 0, and I have had no problems with heat. But If you all are really out to save gas I would suggest checking out 4 things, cheapest being tire air pressure, check it regularly...#2 switch to a good full synthetic oil, i like Mobil 1, noticed a big difference, dont know exact % though...and #3 look at the type of tires you are using, if you are using aggressive soft compound tires youll never get good mileage, need a street tire... rolling resistance kills mpg's, and lastly #4 if you have exhaust leaks up front, its gonna mess with your 02 sensors creating a lean condition and causing the computer to put more fuel into the mix... well Hope this helped good luck... Jay
Or is it that the thermostatic control has nothing to do with the clutch engaging/disengaging during cold startup? This control only applies at its operating set point temperature (I would guess somewhere around 150-180 degrees)
So far, my clutch roars and drags my engine a little during cold start run. But after a few miles, clutch finally disengages and then only engages when I idle for so long and temp really warms up behind the radiator.
THE ULTI-MOD
Joined: Jan 2007
Posts: 19,797
Likes: 36
From: Union NJ
RE: Clutch fan vs electric fan
ORIGINAL: fyjimophreak
Did you have any luck finding a kit to swap out the electric for the clutch fan? I'm looking to do the same thing in my finace's 99 D. Living in Wisconsin it has a hard time warming up (it just barely gets up to temperature by the time she get's to work) and her mpg is horrible. I've looked around a little bit to find a kit for her car, but without any luck. I was reading some of the other posts and I already changed out her water pump (different issue, it was leaking) and the coolant and thermostat so I know those are all good. If anyone knows where I can get a kit, either specific or generic, I'd appreciate it.
Did you have any luck finding a kit to swap out the electric for the clutch fan? I'm looking to do the same thing in my finace's 99 D. Living in Wisconsin it has a hard time warming up (it just barely gets up to temperature by the time she get's to work) and her mpg is horrible. I've looked around a little bit to find a kit for her car, but without any luck. I was reading some of the other posts and I already changed out her water pump (different issue, it was leaking) and the coolant and thermostat so I know those are all good. If anyone knows where I can get a kit, either specific or generic, I'd appreciate it.
