cooling issue

Discussion in 'RND Fabrication' started by toytech93, May 8, 2011.


  1. toytech93

    toytech93 Farmall Cub

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    I have a '79 scout II that installed a RND radiator in before winter. Now that it getting warmer here in NC, I've been trying to control the cooling issues. I've made my own shroud and mounted 2 "10 fans just like your photos posted in the other thread.

    On the trails or slow moving traffic the temp creeps up over 200, the truck has a new 180 t-stat,waterpump,radiator.

    To me it seems the small 10" fans aren't moving enough airflow thru the radiator. Would you have any ideas that might help ?
     
  2. toytech93

    toytech93 Farmall Cub

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    Last edited: May 13, 2011
  3. Dakota Diesel

    Dakota Diesel Farmall Cub

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    Has that fan set up fixed your problem?
     
  4. John Donnelly

    John Donnelly Administrator Staff Member Administrator Moderator

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    You do realize that a temp of 200 to 210 at slow speeds is nothing to worry about, right?

    Because if you are worrying about it you shouldn't at slow speeds. It is if the temperature of the engine continues to climb and climb out of control that you have a problem.

    -John
     
  5. SparkyBinder

    SparkyBinder Farmall Cub

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    I apologize for the late response, but the 10" fans we sell are able to keep the stock 345's cool. Having said that, location, motor condition and tuning also play a large part in that. The Derale fans are very good and sounds like it helped out. As mentioned by John, 200-210 at slow speed isn't much to worry about. Is your alternator a stock unit? If so, you might need to increase the rpm at slower speed / idle to make sure the battery is supplying the fan with enough power to reach full cfm.
     
  6. timscout1

    timscout1 High Wheeler

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    Even with the new radiator and fans you need the correct thermostat that blocks off the bypass and forces the coolant thru the rad. not let it recirculate thru the engine, Do a search for Robertshaw thermostat and there will be lots of reading why??
     
  7. Erik Morton

    Erik Morton High Wheeler

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    Have you verified both fans are working?

    Two good 10" fans work but not all fans are created equal. I have always liked the Derale line. Typically they will have a number of fans for each size capable of supplying from a few hundred CFM up to a couple of thousand CFM.

    Either way as John noted 200-210 slow operation is OK.
     
  8. chazJB

    chazJB Farmall Cub

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    Hello all just thought I would put in my 2 cents about this topic.

    Here is a little back ground:

    I also have the RND alum radiator and was having cooling issues with my 345 with a single 13in fan while I was at a slow or stand still. On many occasions it would get to 240 and at one point sitting in the wonderfull line at DEQ it got to 260 before I was up and told the DEQ worker that I would have to come back so that I could get some driving flow throught the radiator. Now I wanted tobe able to go camping (my camping is not going where the paved spots are by the lakes. I mean real camping off the beaten path) and not have to worry about overheating while I was going slow so I looked into what options were out there.

    During my search I did find that RND makes a dual 10" fan set up but after doing a little math the two 10s did not cover as much surface area as the single 17" did. So I went with the same fan as toytech93. This fan is a two stage fan so I wired the low setting to my through radiator switch wich turns the fan on at 200 degrees (my thermo opens at 180 degrees allowing 20 degrees before the fan kicks on) and the second stage to a switch inside the cab for if/when I needed it on the trails.

    The results:

    I drove my scout for a few weeks before going camping to make sure that I wasnt going to have any issues.

    Well last weekend I went camping and drove on some hairy trails to get there at a slow crawl, The gauge got to 200 and the fan kicked on low. Once this happened the gauge almost immediatly went back down to 180 and sat there the entire time I was cruisen around. Never turned on the high setting at all.

    Needless to say my problem is fixed.
    Good luck to you all.

    James
     
  9. Dkminors

    Dkminors Farmall Cub

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    I'm curious if anyone using the dual 10 in. fan setup on these radiators has had luck keeping temps low. I may need to scrap the dual setup and go with a derale as you have done.
     
  10. SparkyBinder

    SparkyBinder Farmall Cub

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    we have many of these with the dual 10's that are keeping cool. But we've found for warmer areas, built motors, hard core wheeling, etc, the 17 2-speed fans work much better.
     
  11. Erik Morton

    Erik Morton High Wheeler

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    Not all 10" fans are created equal. I thought so and using two 10" fans from Summit, later determined to be TCI supplied, I often had to resort to using my heater to keep the engine cool. While those fans had an 800 CFM rating that was only in free air. They could not draw enough air across the radiator. I have since swapped one of them out for a SPAL 11" HP fan. That thing is a beast. I am still finishing the install but so far it is doing its job very well. Just commuted in on B'mores wicked west side beltway and the fan has very good control of engine temperature. Because of its depth I did have to modify the SPAL frame mildly to fit around the water pump pulley.
     
  12. Dkminors

    Dkminors Farmall Cub

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    I changed the two 10" RND fans out for two 10" SPAL fans and dropped my temp from about 230 down to just over 200 (the point where the second fan comes on). I suspect back in an area of high humidity those less robust fans work fine, but where I am with lower humidity and moderate temperatures they just don't cut it.

    Having never had problems with the stock cooling setup I was a bit surprised to have problems with the dual fan setup. I suggest you may want to either recommend a fan setup based on geography/conditions or just upgrade your supplied fans so other folks don't go through the hassle of needing to upgrade new fans.

    Aside from the fans I'm happy with the setup. Thanks for the help.

    In case anyone is interested the fans I picked up were a snug fit in the shroud from RND but they did fit in the same footprint although I needed different mounting holes. From a clearance standpoint I may still make some changes due to the very close proximity of the fans to the pump pulley facing where the mechanical fan had been.

    The SPAL fans I used are model 30102057. I'm attaching a pic so you can get an idea of the minimal clearance.
     

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