heat problem with J.D 997

Discussion in 'Mechanic and Repair' started by Tonyr, Aug 25, 2005.

  1. Tonyr

    Tonyr LawnSite Bronze Member
    Posts: 1,973

    I have a heating issue with a new John Deere 997...


    see in the pic below, the black mesh screen at the back of the mower...the radiator fan sucks in through that to suck through the radiator.

    this screen obviously clogs very fast....10mins.

    about every 1.5 hours it simply overheats.

    It was suggested I stop every 10 mins and clean it...you can imagine how I felt hearing that! not cheap these units, should be a lot better set up.
    $30.000 aussie dollars.

    the screen isn't even the corrugated stuff, just flat screen, bloody amazing! bloody cheap!

    It's sitting at the dealers waiting for someone to think how to fix it, I think they were going to try to get a new heat switch, this alarm cuts in at 92 degrees and won't cut off. Unless the radiator cap pressure is released which tricks the sensor, then it goes again....this will only allow the alarm to turn off when the correct temp. is reached though.

    But that's one problem....#2 problem is then how to keep the screen clear so the radiator can breath, as the switch won't cure that, and the bloke reckons 92 sounds about right, but no one knows as info is limited on these at this time.

    The screen blocks up, radiator fan can't suck in fresh air, so it gets hot.

    So until deere in America redesigns a better bum for my mower, I'm going to be having problems.

    Now, I did suggest to dealer I put 1 or 2 of those 12v radiator cooler fans in behind the screen to automatically turn on every few minutes to blow the debris off.....dealer said '' do what ya want mate, but we can't cover it, and doubt a 12v fan could have enough grunt to blow out against the suction that is there!''

    We put a towel size cotten rag over the screen yesterday, it sucked it on pretty well, certainly wouldn't fall off....so dunno how good these 12v fans really are?

    They cost about $100 each....dunno if it is worth trying or not....

    Anyone got any ideas?


    The new Hustler diesels have 2 of these 12volt radiator fans on a auto reverse system, they cool the radiator, then every set interval they reverse for a few seconds to clean it, these are the only fans on their radiator as the engine is sideways, leads me to think these fans providing they are the same as what you can buy from aftermarket auto shops would have plenty of air force.

    I appreciate any comments, suggestions, feedback, advice.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Possibly mounting one of them aftermarket fans on top of the radiator blowing down on the front would redirect the debris from the screen ?
    It's hard to believe a problem like this passed the infield testing ! Or they just had a don't care get it on the market attitude. :dizzy:
     
  3. Tonyr

    Tonyr LawnSite Bronze Member
    Posts: 1,973


    That's how I'm seeing it mate....especially putting a rear discharge deck on a mower that breaths from the rear...where it is dusty, just makes me wander how it passed.

    I think these aftermarket radiator 12 volt fans are going to be the best way to clear that rear screen if auto turned on every 5 mins for a minute or so, providing they will fit between the big oil cooler which is behind the radiator in behind the screen....

    When I get the machine back I'll see if one or 2 fans can squeeze in there, and just blow the crap off the screen from inside intermittently.

    I can't think of any other solution as to clearing that screen automatically.


    I haven't seen one of these 12v fans working, do you know if they push a lot of air or not, or how could you describe their performance?
     
  4. heather lawn sp

    heather lawn sp LawnSite Senior Member
    Posts: 681

    You and that machine are really not the best of friends are you? We are at about 170 hours. 997 comes back after an hour or two with the screen MOSTLY covered. Is it mostly grass clipping or is it a lot of dust too? We didn't overheat even in our exceptionally dry July this year. Not wanting to bring up THIS old topic again, but... could the rear discharge be pushing the clippings UNDER the mower to be sucked up by the air cooling intake at the rear?

    1. Build a wind deflector to extend the bottom plane of the mower back so the suction of the intake can't get to the clippings before the clippings hit the ground. Maybe just start with a cardboard step of a foot or two back and across the back of the rear cowling taped to the cowling to see if it improves it at all

    2.Convert the rear discharge to mulching as discussed earlier.
     
  5. heather lawn sp

    heather lawn sp LawnSite Senior Member
    Posts: 681

    also

    check the space between the rad and the oil cooler. Oil cooler swings away from a thumb screw. Alot of dirt gets trapped in there and blocks the cooling fins
     
  6. Tonyr

    Tonyr LawnSite Bronze Member
    Posts: 1,973

    Hi mate,

    the things I tried when messing with clipping flow on that deck would of made them land just after cut, it is because it is rear discharge, doesn't matter if I'm mowing turf or paddock, wet or dry, the deck still creates enough stuff to get sucked up.

    the rd deck cuts clippings very fine, semi mulches.

    a mulch deck is too limited for my work.

    Funnily enough I don't get a bad build up on the radiator, obviously in the dusty dry stuff I do but only a bit behind the cooler, which I clean throughout the day.

    The screen totally, 100% blocks fast on my mower, even over the air intake area, but dealer doesn't want to put a donaldson precleaner bowl up behind the seat to suck cleaner air....makes money out of selling filters at $47 each I spose!

    The fact is....I did not add an aftermarket deck to this mower, it is new, it is a factory essembled unit, it should of been tested, while ya bum points to the ground running a rear discharge deck on a short mower ie ZTR, and having the cooling system sucking from the dustiest area is not smart engineering and will be a problem till fixed.

    and no...the clippings don't fly out the back...only dust and fine debris that floats in the air flow....more dusty fibrous stuff.

    once we get 'er all going I'll be mates with my mechanical Shrek again....I've given up on the windrowing thing, just double cut the windrow areas, I'm at peace with it.
     
  7. Guthrie&Co

    Guthrie&Co LawnSite Senior Member
    from nc
    Posts: 784

    i would try this before i did anything else.

    wash the radiator out with purple power or some other degreasing grime removing agent. i would do this several times letting it sit between washings for a few mins. i have had to do this with a few tractors that would overheat alot. what i found was that the dust and debris would clog up the ducts between the fins and not allow air to past though. some simple green and a strong stream of water might help you out. by the way the best time to do this is in the am when it has sat overnight to cool. do not do this when it is hot. let me know what you find. i bet it helps
     
  8. riches139

    riches139 LawnSite Senior Member
    Posts: 369

    Why would they use a system that sucked air "in" through the radiator with all the debris coming out the rear? :realmad:

    The Cub Cadet tractor I had, drew in air from under the dash and forward to the engine and out the front.

    Seems to me you could use electric fans to reverse the air flow as long as you had a couple of inlets on the engins shroud.
     
  9. Tonyr

    Tonyr LawnSite Bronze Member
    Posts: 1,973

    thanks guys...

    the radiator has been throughly cleaned and checked my deere mechanics as they thought it was just a case of a dirty radiator....

    anyone know much about the corrugated screening that toro, exmark etc uses?

    I know it would have a lot more surface area, but would it still clog or does the corrugation style tend to not clog?
     

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