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Liquid vs air cooled agree or not?

Discussion in 'Lawn Mowing' started by tacoma200, Oct 16, 2007.

  1. tacoma200

    tacoma200 LawnSite Fanatic
    Messages: 5,426

    Here is how one company explains liquid vs air cooled ZTR's. Do you agree?

    What are the advantages of liquid-cooled engines vs. air-cooled engines?

    Generally speaking, it is said that a liquid-cooled engine "may" last up to 50% longer than comparable air-cooled engines due to a constant, correct operating temperature. Engine oil viscosity does not break down as quickly due to the more stable temperature ranges at which liquid-cooled engines run. Liquid-cooled engines experience increased fuel economy compared to standard air-cooled models due to the more consistent operating engine temperatures. A properly designed system keeps the radiator out of harms way (debris, branches, etc) and the cooling fan draws hot air through the radiator, past the engine and away from the operator. This results in a cooler engine and a cooler operator.

    Liquid-cooled engines are slightly more “forgiving” if the exterior of the engine is not kept clean, unlike air-cooled engines that rely upon heat dissipation for proper cooling. There is little extra maintenance involved with a liquid-cooled engine versus an air-cooled. Keeping the radiator clean is the biggest factor. However, this is simple to do by using the removable screen that can be removed and tapped clean in the field, with no tools required.

    The major benefit of an air-cooled engine is that they are simpler in design as they have fewer parts involved. Because of this, they are less expensive in price and potential repair cost.
  2. SproulsLawnCare

    SproulsLawnCare LawnSite Senior Member
    from IN
    Messages: 365

    For the most part, I would have to agree. All of the arguments for the liquid cooled engine make sense.
  3. Langford2000

    Langford2000 LawnSite Member
    Messages: 222

    The only part I see as incorrect is that the fan draws fresh cool air over the rad then blows over the engine. The above say it draws hot air which is incorrect
  4. Greenguy1

    Greenguy1 LawnSite Member
    Messages: 103

    One of the most important things to do with an air cooled engine is to allow them to warm up before increasing the rpm. Since there are more temp. swings with an air cooled eng. the engineers have allowed a looser tolerance in the cylinder to accomodate this, therefore when the engine is cold the piston is slopping around in the cylinder, which could lead to premature cylinder wear if not allowed to warm first, I have Vangard engines with 4000 hours on them and have very little oil consumption and they are air cooled.
  5. Daddio

    Daddio LawnSite Member
    Messages: 20

    I agree,but the extra weight and cost of liquid is far short of its benefit.
  6. TAZ

    TAZ LawnSite Senior Member
    from Ohio
    Messages: 344

    I do question the longevity numbers. I agree with you to an extent. The oil issue and more consistant temperatures overall seem logical.

    My take on it is a little different from my experience in motorcycle engines. Seeing that the consumer wanting more powerful machines and the designers are forced to meet increasing EPA specs they are leaning these engines out to meet the HP/Emissions requirements. Leaner jetting means decreased performance and increased heat. The liquid cooling combats that to a large extent but some areas like valves are harder to cool. This is my first water-cooled engine. We'll see how it goes.

    I would look for more of these engines to start creeping into the market as well as catalytic converters in the near future. Off road engines are not under the same scrutiny as over the road engines but it's coming.

  7. Oldtimer

    Oldtimer LawnSite Bronze Member
    Messages: 1,459

    Coolant Replacement
    Water Pump - driven by belts and additional pulleys or an additional
    hydro pump w/pulleys, belts, hoses & check valves.
    Radiator w/hoses
    Cooling Fins
    Radiator Shroud
    Over Temp Alarm
    Temp Gauge

    Heck of a trade out to keep from cleaning cooling fins. Engine life is usually shortened by the owner or operator trying to cut corners on maintenance, failing to read their owners manual and just plain abuse.

    All the air cooled engines used on real commercial mowers are world class and, if properly maintained will give 2000 - 4000 + hours of service. That is longer than most LCOs keep a front line unit.

    There are many posts from LCOs looking for cheap filters and trying to keep from purchasing original equipment parts. As a dealer and former LCO I can see both sides of the picture but using OEM parts will add a very few dollars and will assure the owner he is getting the best parts available for maintenance plus the longest life from his engine.

  8. tacoma200

    tacoma200 LawnSite Fanatic
    Messages: 5,426

    I have nothing against liquid cooled engines but I see things your way to a large extent. A lot to be said for simplicity and most trade ZTR's before the 2,000 to 3,000 mark.
  9. Pietro

    Pietro LawnSite Senior Member
    Messages: 855

    I own both. I have a toro 60 diesel 23 and a gas 48 kawi 23.........my dealer told me the kubota diesel will last me 6K hrs if I take care of it..........whereas the gas will not........so liquid is better if you keep up with it???????? I am a firm believer of "you get what you pay for"..........and I take care of my stuff..........so I put my money on liquid cooled.
  10. Oldtimer

    Oldtimer LawnSite Bronze Member
    Messages: 1,459

    I began selling Z mowers in 1992 and haven't experienced and engines that wouldn't run 2000 hours plus if they were maintained properly. I saw a Walker owner trash a 16HP Kohler Magnum in 60 hours and I know of a 25HP Kohler Command that made >6000 hours.

    The Kohler EFI engines are really durable when properly maintained. I feel the EFI engine is good for a minimum of at least 4000 hours and it is very easy on fuel. My service department was a beta site for the Kohler EFI software and I have a couple of techs who really understand the system.

    The Kawasaki liquid cooled engines seem to run forever with good maintenance.

    It's a personal choice as to which engine is best and it's a personal choice about how to take care of the engine to get it to run out and not break down.


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