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Fan clutch or electric?

Discussion in 'The Garage' started by BanksBurban, Dec 23, 2003.

  1. BanksBurban

    BanksBurban Registered Member

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    My diesel burb needs a fan clutch. NAPA says $109. Has anyone eliminated the stock fan and ran an electric? Experiences? Reliability? How much would an electric fan with all the controls to have it come on and off by itself run me?
     
  2. HarryH3

    HarryH3 1 ton status Author

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    The factory fans pull WAY more air than any electric fan that will fit under the hood can move. Diesels can make a lot of heat when they're working hard. Just compare the size of your radiator to that of a 350-equipped truck. /forums/images/graemlins/shocked.gif There is a dual fan setup on the market that is aimed at gas powered trucks, but it costs about $400. /forums/images/graemlins/eek.gif Plus, when you have 2 fans pulling 25+ amps each, you can quickly overpower a stock alternator. So now you're looking at an alternator upgrade at $100-400. /forums/images/graemlins/eek.gif

    NAPA always has the highest prices around here. Often by at least 20%. Try calling around to other stores in your area. You should be able to find a heavy duty fan clutch for closer to $80 if you shop around. /forums/images/graemlins/cool.gif If someone quotes you a price in the $40 range, then there's a 99% chance that they're quoting you the standard duty fan clutch, which won't live long in your application. /forums/images/graemlins/frown.gif
     
  3. camok5

    camok5 1/2 ton status Premium Member

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    I just switched to an electric from flex a lite(dual fans with thermo controls) and there are pros and cons. The pros are that it cleaned up the front of the engine and made it easier to get to everything, plus it does a great job keeping an even temp. The cons are it cost about $500 and the brain box that controls the thermostat sucks(goes on and off to much and lets the engine get too hot before it kicks on). In the end I just ended up running the fan off of my ignition which is ok in Southern California, not to cold on warm ups. I could have saved myself alot of money if I had just bought electric fans without the thermo controls. I still like it better then the stock fan clutch style... /forums/images/graemlins/thumb.gif
     
  4. Burt4x4

    Burt4x4 3/4 ton status

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    I run both....elctric is mostly a backup durring the hot season.
     
  5. 99firehawk

    99firehawk 1/2 ton status

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    I have a set of dual electric fans off a 97 lt1 camaro, it keeps my 350 powered k5 nice and cool, I used to use the same fans on my blown 355 in my old ta also.
     
  6. darkshadow

    darkshadow 1 ton status

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    i was thinking of going electric but my idea is to go to pick and pulls and pull one two hell for the price three or four electric fans and rig something up my self. /forums/images/graemlins/grin.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/burb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  7. camarine

    camarine Registered Member

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    Running custom dual electric. 2 14" fans at 68.00 each and an adjustable thermo control for 28 bucks. I love it, if it gets too warm for my pleasure i flip a switch and it plummets dramatically. I also had to upgrade to a 100 amp alternator to run them but that is just setting me up for dual batteries. Depending on what you do with your truck if you run electric or stock.
     
  8. Triaged

    Triaged 1/2 ton status

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    Engine driven all the way! Electrics need alot of current from the alternator and arn't as reliable as engine driven. Right now I have a flex fan because it was on the motor when I got it. I will be swapping in a clutch fan sometime.

    The best fan in my book is one with an electric clutch that is driven off of the motor! They use them on Semi's and make kits for some of the newer diesel pickup motors.
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I'm going to run both, I think.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Electrics need alot of current from the alternator and arn't as reliable as engine driven.

    [/ QUOTE ]

    MIght be true with a flex fan, but clutch fans are arguably just as failure prone as electrics.
     
  11. 85 blazer

    85 blazer 1/2 ton status

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    I use 1 from a t-bird one speed hooked to a sensor and relay to turn on at 190 other (high) to a relay and override switch never over 160 down the road and 200 WFO in the mud!!! Electric all the way
     
  12. BanksBurban

    BanksBurban Registered Member

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    I tow and plow with this truck, so it sees hard highway use.
    The clutch on it now lasted less than three years.
     
  13. BigRed89

    BigRed89 1/2 ton status

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    I highly recommend going with an electric fan. If you don't want to search the junk yards and simply want to buy one with everything you need, the Flex-a-lite Black Magic is hard to beat. It pulls 2800cfm and draws 13.9amps. The cost can be prohibitive at $200 from JEGS or Summit. If your charging system is not already tasked with auxiliary lights, amps, or other after market electrical goodies, your stock system should be able to handle it. The Black Magic fan comes with an integrated thermostat so you can set when you want it to turn on. I have personally used these fans on three vehicles now without any problems.

    Like camok5 stated, electric fans help to clean up the front of the engine making it easier to work on your rig, as well as there is less parasitic drag on the engine since the crank no longer has to turn the fan.
     
  14. HarryH3

    HarryH3 1 ton status Author

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    Drop by your local GM dealer and take a look under the hood of some new trucks. While many (if not all) GM cars come from the factory with just electric fans, you'll find that trucks still come with clutch operated, engine driven fans. You can bet that if GM thought they could get away with the electric fans on their trucks, in the elusive search for another tenth of a mile per gallon, they would do away with the engine driven fans. But many trucks get driven hard, dragging trailers that are way too heavy, up long steep grades in 100+ degree heat, at WOT and often at low speeds, with the A/C blowing on high. This is when cooling demands are at their highest and the engine driven fan is moving tons more air than an electric fan could. The only factory electric fans that I've seen on GM trucks have been secondary fans on big-block equipped trucks with a heavy duty cooling package.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Drop by your local GM dealer and take a look under the hood of some new trucks.

    [/ QUOTE ]

    GM also stuck with carburetion up until 1990 on some V8's in the states. The only reason GM will do something is to meet emissions standards (CAFE or otherwise) or save money. If the clutch fan saves GM one penny on every truck they sell, they will stick with it. With trucks not having to meet the same emissions standards as cars, I doubt every MPG is a real concern, or else they'd all be filled from front to rear with synthetic lubes, etc. from the factory. (to my knowledge, the trucks are not)

    You'd have to see a cost breakdown between the two setups to know for sure, but electrics require a lot more components (even more with larger CID) than a clutch fan. (a 305 or 350 dual fan setup from GM, like in a Camaro, could be two relays, two temp switches, all additional wiring and connectors for two fans, aux. junction block between battery and fans, fan relay fuse/wiring, fusible links, etc., all unnecesary with a clutch fan)

    Besides, you can't cool a tranverse mounted motor (modern FWD) with a clutch fan, and electric fans can allow for a lower hoodline, more radical radiator shapes and placement, and a shorter front end. Arguably, none of these are necessary to consider (or at least apparently none are much of a concern except perhaps nose length) on a truck.
     
  16. BanksBurban

    BanksBurban Registered Member

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    I have one of those secondary electric fans from an 87 1 ton big block 4x4 I parted out. I don't know if it will fit the diesel radiator support or how it's controlled? Does anyone know? I was thinking of reducing the strain on the waterpump bearings when I came up with the idea of switching to electric fans. Either way, it's going to cost me at least $109. I figured if the cost was relatively close, it might be worth switching, but I don't want to waste money on something that won't work. The diesel radiator is bigger than even the big block radiator w/ HD cooling, so I have a lot of room to work with.
     
  17. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Dorian,

    You hit it right on the head. Today's cars are taxing the alternator output that they do have already with all the electric goodies they've got. Since a bigger alternator is not cost effective, the manufacturers will stay away from electric fans.

    I'm still not convinced that an electric fan on a truck can take care of everyone's cooling needs, but for most of us it can be made to work.

    I guess I'll take off my mech fan and give it a shot after I get my aux. electric.
     
  18. HarryH3

    HarryH3 1 ton status Author

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    I've yet to see an electric fan setup that's rated for more than around 250 HP. Sure, there are folks that run 500 HP engines and get away with those fans, but they are seldom using more than a fraction of the engines HP for more than a few seconds at a time. The rest of the time they are idling around town or cruising down the freeway at 70 MPH. Neither of those situations require much cooling, as the engine just isn't working hard.

    Around here it is not uncommon to see trucks pulling trailers up 6-7% grades at WOT for many miles at a time, while only moving at 20-40 MPH. THAT will put a hurtin' on a cooling system. I wouldn't want to depend on just electric fans in that situation. When the clutch on the fan of our '94 Sub kicks in, you can feel the truck slow down slightly, and hear the roar of air being pulled though the fan. That sucker moves a LOT of air. And when the a/c is running, it doesn't take long at all for everything under the hood to become WAY too hot to touch without gloves. Just checking the oil will burn your fingers. /forums/images/graemlins/eek.gif Oh yeah, that's without towing anything. /forums/images/graemlins/shocked.gif

    I have dual electrics on the K5 and they work fine because it seldom gets tasked to work really hard (and the a/c hasn't been hooked up in years). But I'll stick with the old school engine driven fan for the rigs that are called upon to work hard for long periods of time. /forums/images/graemlins/thumb.gif

    As for failure rates, I've only had a single clutch fan fail in any of my junk for the last 25+ years. /forums/images/graemlins/cool.gif
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    I've yet to see an electric fan setup that's rated for more than around 250 HP.

    [/ QUOTE ]

    You mean like all the Corvettes and F-bodies? /forums/images/graemlins/smile.gif

    I understand what you mean though...the cars cooling systems aren't being taxed for long periods of time at full load. Typically the vehicle is moving fast enough that fans are irrelevant, as the air coming into the engine bay is moving faster than the fans can pull, so they aren't even working.

    As long as engine RPM is high enough, (equal to around what the fans effective RPM is) then the clutch fan is effective. The problem with clutch fans is that if the RPM of the engine isn't high (and on most diesels, I don't think it EVER is) then the cooling isn't very effective. Again, this would relate to how GM designed the clutch fan setup. With the electric fans, every time they turn on, they are just as effective. (ignoring external influences like vehicle speed, etc)

    I would say that in a situation as you describe, an electric fan setup might be iffy. But if you went with a high CFM dual fan setup (somewhere over 5000CFM combined) then I don't THINK you'd have problems. The real issue is that the CFM rating of the various factory clutch fan setups isn't known. I don't think I'd trust anything much under 5000CFM for cooling a hard working vehicle, or one that spent a lot of time in a hot climate at slow speeds with a 350 or larger.

    It would be guesswork, and if you have to drop the money on an electric setup to find out later on it really doesn't work in your application, you'd be pretty mad.

    If you were going with a fan clutch again, if you didn't the first time, go with a Delco replacement. Is your front air dam in place too? Every little bit helps.
     

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