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Cat – Standard Fan vs On Demand Fan

DirtCrawler ยท 2014-10-29 23:23

Is the on demand fan a worth while upgrade from the standard fan or no? The on demand fan just runs when its needed correct, where the standard fan would be running all the time? Thanks

Replies7
  1. #1durallymax2014-10-30 00:23

    AFAIK yes, all of ours have the on demand fan and it's nice not having a fan making noise, burning fuel and sucking trash into the engine compartmwnt. Unless you are looking at D series then the latter isn't as big of a deal. It will only run as needed and every once and awhile with do a quick burst to clear the dust out of the coolers.

  2. #2Nige2014-10-30 08:04

    What machine model are you talking about and what sort of operating conditions such as ambient temperature, airborne dust, altitude, etc, do you have....?

  3. #3DirtCrawler2014-10-30 23:15

    Looking at the "D" series. I was looking at the Demand fan on the issues of like durallymax said 1)constant fan noise 2)fuel savings. And I was looking at it from the stand point on winter use, why would I need the standard fan running all the time in the winter if outside temperatures would help or may even prevent the demand fan from even running. Or is that a non issue? Also wouldn't the standard fan constantly be borrowing resources from the engine all the time vs the demand fan only asking for whats needed when needed? Probably wont be in a lot of extremely dusty environments, but will have dust from driveway. Not in the mountains.

  4. #4Nige2014-10-31 09:24

    Everything you say is correct in theory, I can't say I've ever seen measurable gains in practice. We used demand fans on larger equipment at high altitudes to remove the power drain from the fixed fan (a big engine it can be around 100 HP drain) so in some way compensating for the power loss due to altitude, and to avoid overcooling of the engine compartment in cold ambient temperatures. Any idea what make of demand fan clutch it is..? Some were more reliable than others.

  5. #5tmc_312014-11-02 10:45

    Small savings for extra cost on the front end and something else to break. Just my opinion. Tim

  6. #6JDOFMEMI2014-11-02 13:40

    Yes, and while I have no experience with it on a skid steer, on larger equipment it is one more problem to troubleshoot. It took the dealer well over a week to diagnose the overheating problem on my D-8T because the system seemed normal, but the fan speed would not speed up enough with the higher temps to cool the engine.

  7. #7durallymax2014-11-05 18:16

    Its a hydraulically driven fan regardless, the demand fan just runs the speed/frequency its told to where the other one runs wide open all day. I don't know what the cost is upfront but I certainly wouldnt expect a payback in fuel savings, its not using that much power. Maybe if you had a fleet of 10 running 3,000hrs per year you would see a huge benefit. I have never ran one without, our dealer orders most all of them with it.