How do I diagnosis a head gasket issue Kohler Command 18 Hp

Discussion in 'Mechanic and Repair' started by Gulkanariver, Dec 27, 2012.

  1. Gulkanariver

    Gulkanariver LawnSite Member
    Posts: 14

    I have a 2004 Toro Z Master model # 74162 mower. It has an 18 HP Kohler Command single cylinder engine model number CV 493S Spec #27529. I have 570 hours on the mower. How do I check for a blown head gasket.
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  2. BigFish

    BigFish LawnSite Gold Member
    Posts: 3,068

    Well, if it's not running, or was smoking like a big dog, just pull the head off......it ain't gonna fix itself.

    But I digress............

    I use a cyl leakdown tester, but you can check it with just an air blowgun.
    Pull the valve cover.
    Bring the piston up TDC on compression stroke, hold the flywheel/crank securely( however you wanna do it) and push a little air in the spark plug hole, and listen for air in the pushrod galley and/or all around the outside of the head.
    The Slapper, AKA Mr. Kohler, might be able to offer up some ideas...........
     
  3. Gulkanariver

    Gulkanariver LawnSite Member
    Posts: 14

    I bought the mower about a month ago for $500. Only has 570 hours on it. The guy I bought it from said it may have a blown head gasket. I've cut my grass a couple of times with it. It may not have as much power as I expected but it still cuts. The oil that drips from the valve cover onto the exhaust may have made him believe it had a blown head gasket.
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  4. Landrus2

    Landrus2 LawnSite Platinum Member
    Posts: 4,811

    Compression text will give a good idea or a leak down text.:waving:
     
  5. Gulkanariver

    Gulkanariver LawnSite Member
    Posts: 14

    I'm going to do a compression test on Saturday. What would be a good compression number for this engine?
     
  6. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    I'm sure it has an ACR so your compression readings will probably be 100 to 120...
    A few questions...
    Does the engine smoke ?
    Is the sparkplug fouled ?
    How much oil does it use or leak ?
    Does the engine make a hissing noise..like air brakes..when you shut it off ?
    Is your oil level too high ? Smell like gas ?
     
  7. Roger

    Roger LawnSite Fanatic
    Posts: 5,917

  8. Gulkanariver

    Gulkanariver LawnSite Member
    Posts: 14

    I've only used it a couple of times but:
    The engine does not smoke.
    The oil is not over filled.
    The oil does not smell like gas.
    I haven't run it enough to foul the plug.
    From what I can tell it looks like about a tablespoon of oil will leak out of the bottom of the valve cover over two weeks.
    The engine does not make a hissing sound.
    I don't believe I have a head gasket problem. I think someone miss diagnosed the oil leak at the valve cover. I'm going to do the compression test in the morning and not worry about it if the compression is at 100-120.
     
  9. Gulkanariver

    Gulkanariver LawnSite Member
    Posts: 14

    Compression is about 118. I'm going to service the mower, fix the oil leak at the valve cover and cut grass. Thank you for all the help.
     
  10. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    The valve cover bends pretty easy....new replacement about $20...
    Check the engine rpms....
     

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