Discussion in 'eXmark' started by H2OandNcutter, Apr 29, 2006.

  1. H2OandNcutter

    H2OandNcutter LawnSite Member
    from Atlanta
    Posts: 43

    Hey Guys,

    Anyone have any experience with adding an automotive oil cooler to the hydro system on a TTHP or Lazer HP? Seems like it would keep the Mobil 1 a lot cooler and increase the capacity of oil used as well.

    The thought came to me when I realized just how hot, and how quickly, the reservoir for the oil gets.


  2. H2OandNcutter

    H2OandNcutter LawnSite Member
    from Atlanta
    Posts: 43

    Hey Guys,

    Anybody out there? Exmark?

    Has this idea never come up before? There is a related question as well. Has anyone ever used an automotive type oil cooler on the engine oil?


  3. martinez

    martinez LawnSite Member
    Posts: 4

    I would think that your idea should work. Race car builders do it, Harley makes a cooler for my bike.
  4. Gruneich Lawn Care Inc.

    Gruneich Lawn Care Inc. LawnSite Senior Member
    from SD
    Posts: 295

    This was talked about sometime ago on here. Seems the general agreement was that it was not needed, as they use mobil 1. The factory also said the fluid doesnt get hot enought to warrent a extra cooler.
  5. tomo

    tomo LawnSite Senior Member
    Posts: 660

    hello, an auto cooler may not work as it may not have enough flow capacity or be able to handle the pressure. These should be checked b4 any cooler core is selected.Then comes the questions physical install, will it be self draining ,will room compromise install ,air flow engine fan or electric dedicated fan [this will require thermostat] altenaror capacity for elec fan required.Will cooler be mounted behind bug screen . You may require bi directional fan control to keep cooler clean if it is not protected from bugs/debris.Cooler selection for easy self clean required. I fitted cooler to walkers of mine in a nut shell DONE PROPERLY COOLERS WORK WELL!!!!!!!!!!!!!!!! As the addition can be costly i suggest you seek advice from a GOOD hydraulic shop then pay your money!!!! Thanks TOMO
  6. tomo

    tomo LawnSite Senior Member
    Posts: 660

    HELO, almost forgot have you measured temp accurately.If the temp only is occasionly at 100 celcius i would not bother with the expense , just change fluid yearly. There are many pitfalls and it is always more costly than you think 4 AN EFFECTIVE MEASURED RESULT. Thanks tomo
  7. Pumper

    Pumper LawnSite Member
    Posts: 116

    Adding a cooler is a great idea. As for flow and pressure, you are looking at about 1 gallon a minute and 20 psi or less. If you tie into the case drain from the pumps before they go back into the tank/reservior, then you are dealing with low pressure. The Exmark circuit REQUIRES the Mobil 1 oil because the tank is so small. The Mobil 1 decreases the system temperature about 15-20 degrees. If they didn't use the Mobil 1, they would surely go over 250 degrees (which is where the oil starts to break down and you get cavitation in the pumps and motors). The cooler you would need is the kind used to cool transmission fluid on trucks with towing options. You can find these for about $20-30 down at Napa or AutoZone. You will need to mount this so that it catches air flow. This is a little more difficult with the horizontal engine but it can be done. The cooler should take out at least 20-40 degrees depending on the cooler and the air flow. Good luck.
  8. H2OandNcutter

    H2OandNcutter LawnSite Member
    from Atlanta
    Posts: 43

    Hey Pumper,

    Thanks for your well stated reply! I have some modest experience, 10 years, in the automotive biz and that's what brought the whole idea to light. Looking at the lines on the pumps and reservoir it seemed pretty clear that not all the lines/clamps represented a high pressure situation.

    Flow and pressure are quite different - it all has to do with fluidics. I've had both high volume and high pressure oil pumps in my cars/trucks over the years . I think high volume is the way to go. However, it didn't seem that the pressure in all the various parts of the Exmark was likely to be more than 50 or 60 psi which I've seen in my cars/trucks. Surely a high performance automotive high volume oil pump is capable of flowing more than the Exmark pump - speculation on my part I admit.

    So, if a good quality automotive grade oil cooler is capable of withstanding high flow and high pressure for tens of thousands of miles then it may be the right thing. Honestly, I'd not thought of the trans cooler. My Dodge 1500 Ram has a nice little factory oil cooler. My genuine Blues Mobile, '87 P-71 Crown Victoria, has a factory oil cooler, trans cooler, and power steering cooler as part of the factory police package.

    So, I was thinking that even without optimal airflow a cooler would lower the temperature of the Mobil 1 some, which has to be a good thing. The set up would also create situation where an additional volume of Mobil 1 would now be in the system, also a good thing. Don't some of the other mower manufacturers use substantially more fluid, as in gallons vs quarts, in their hydro systems? Seems like I read that at some point on Lawnsite. And, perhaps most importantly, it just plain sounded like a cool modification that could be helpful over the long haul. I have every intention of keeping these mowers for the long haul.

    This whole thing got started when I realized the hydro reservoir was too hot to touch in a very short period of time. I guess maybe there really is a reason for those warning decals! And, as we all know, temperature can be our enemy! However, I would have to admit, in all honesty, to not actually measuring the temperature of the hydro fluid.

    So one day whilst mowing I got to think'n about this. I even pulled out the factory paper work to look at the various hydraulic lines and their routing. My hunch is that it wouldn't be very difficult and could be a very nice, cleanly done, entertaining, nearly factory looking installation with a few custom brackets and a custom guard for the cooler itself. I have all the welding equipment I'd ever need for such a project.

    Now the question is where in the system does the new oil/trans cooler go? The answer, I now know, is in the low pressue line between the case drain and the reservoir!

    Thanks for your interest and comments, I appreciate it!

  9. kc2006

    kc2006 LawnSite Silver Member
    Posts: 2,442

    The whole point behing the arguement was.

    Even though we know heat is bad, the fact that the system exmark runs is good for the life of the machine makes it useless to spend the money on building a system that will allow the hydrualic system to last longer then the life of the machine. If you can understand that.

    Transmission coolers in trucks, good idea. When towing, a trans is going to get hot...but they'll get too hot. So you need the cooler to make the trans last the life of the truck (or part of the life). Hydro system in the mower is known to last the life of the mowers already and don't get overly hot...just no need. You'll be blowing engines, cracking frames/welds, just over all dumping money into the mower at X hours while your hydro system is still good basicly.
  10. DEEJ

    DEEJ LawnSite Member
    Posts: 230

    kc2006 could not have said it better. The system on the Exmark works extremely well, for the life of the machine or more, so why spend time and money on something that does not need any improvement? There is no history of damage or early failures of Exmark Hydro systems due to inadequate cooling.

    If your air conditioner cools the room just fine, and you are comfortable, why would you add more air conditioning? Are you better off for it - absolutley not.

    The designers really do have some idea of what they are doing! And the design has stood the test of time.


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