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04 2500 hd

Discussion in 'Chevy Trucks' started by jlb2500hd, Feb 24, 2007.

  1. jlb2500hd

    jlb2500hd Member
    from N.Y
    Messages: 38

    I have a 2004 2500 hd, i had a problem with the truck overheating with the plow, i took it in and had the fan clutch replaced with the new one, now the truck doesn't overheat but it gets up to 250 degrees or so, and the trans. temp gets up to 200 degrees before the fan kicks on and cools the truck, i was reading that when they replace the fan clutch they also program the computer to turn the fan on more often when plowing, is this true?? because i don't think they did that, also now the warranty is up on the truck, i would think this problem would still be covered, any one know for sure?? thanks for the help.
     
  2. I've had similar intermittent experiences with my '02 HD (gasser 8.1L) with plow on going down the road. Its wierd..."Check temperature" or something comes up, and I look and its up to 260 or so. I ussually lower the plow and keep driving and it goes down (I ussually am very carefull with plow height...just enough to not hit ground over bumps...seems like a matter of only an inch or so difference). It sorta lingers hot for a few seconds, minute maybe, then drops suddenly in about 2 distinct, rapid decreases until it reaches normal temp. Trans cools down more progressively.

    I kinda wondered if its a thermostat or something the way it drops so fast (this might be stupid, but does my truck have a thermostat?). I guess it could be the fan...but isnt it a temperature sensitive fluid type clutch or something? I dont think there are any wires going to mine...or is there?

    Hope someone chimes in...
     
  3. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Some guys still have heating issues even with the upgraded clutch fans. Sometime's it's just necessary to play with the blade position until you discover where the truck runs the coolest. The way a temperature sensitive clutch fan operates (which is the type of fan these trucks have) is theres a coiled bi-metallic spring mounted on the front of the clutch that senses the temperature of the air coming through the radiator. As the air gets hotter as it hits the spring it causes the spring to unwind which turns a lever inside the clutch fan,thus engaging the fan. Being that the fan is regulated strictly by how hot the air is coming through the rad it is totally dependent ON that airflow to activate the fan. Now you go and hang a plow on the front of the truck which disrupts the air through the radiator and now the fan can't "sense" the hot air from the radiator.The upgraded fan clutch's just have a lower "engagement" temperature setting to deal with the reduced "airflow sensing" through the radiator. BTW mr_udy, yes your truck still use a conventional thermostat in the cooling system. :)
     
  4. B&B: Awesome description on "how it works". Thanks!

    I have plow prep package..so I guess I have lower temp engagement fan.

    Any way to tell if fan is working? Heat gun or something? Prior to me cranking it up a few inches and bigger tires (total increase of about 3-3.5" in height), I remember driving with the plow and you could hear/feel fan running sometimes...loss in power. I have not heard/felt it since...even when it runs hot.

    I try to run plow as low as possible. I see some guys running it all the way up-I wonder if up gets air from underneath. Sorta wondering if I am crating a negative pressure area in front of radiator from air rushing over plow and up over hood...so like you said, no hot radiator air running over fan clutch... Guess I got some experimenting to do...up, down, angled, etc...

    Thanks again!
     
    Last edited: Feb 24, 2007
  5. hammerstein

    hammerstein Senior Member
    Messages: 318

    My 04 only overheats with plow on when the outside temp gets over 40. I did have the fan clutch replaced once under warranty and keep the blade low to the ground while driving if it is above freezing. With engine shut of you can spin the fan blade there should be resistance as you spin it and should not spin freely.
     
  6. jlb2500hd

    jlb2500hd Member
    from N.Y
    Messages: 38

    I have also heard somewhere that the computer can be programmed so that the fan runs more often is that true??? Also you might have a point about keeping the plow up, it may allow air to run underneath it and thru the radiator, so far i have had the best luck with the blade straight instead of angled, it seems to stay cooler, i just don't like seeing the trans. temp get so high and take forever to cool down. I thought about running a cooler thermostat in it, but wouldn't that put extra strain on the cooling system itself???
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Only trucks that are equipped with electric cooling fans, can be reprogrammed through the PCM to operate at a lower temp (since the electric fans are controlled by the PCM). The HD's have an engine driven fan.It's up to the clutch on the fan to decide when it needs to engage to cool the engine under demanding conditions. Thats why adding a plow causes overheating problems,the clutch can't "feel" the heat coming off the radiator due to the airflow being disturbed by the plow.
     
  8. Anyone add an electric "Pusher" or "Puller" that could be thermostatically or manualy controlled?