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912 uls Blew out coolant

in 912 / 914 Technical Questions 6 years ago
I just had an coolant problem and it emptied my reservoir . Not even sure where it came out . Could it be a bad cap? I don't see any problems and the CHT never got near the red.
It was a hot day in a heavier than normal climb out.
I Ordered new hose and clamps I plan to start there as it could have leaked past the clamp. I tried to get it to leak somewhere but nothing leaks under normal operation.

  • Re: 912 uls Blew out coolant

    by » 6 years ago

    Are you saying you had to add a Gallon+ to refill the whole Cooling System, or just a Pint to refill the Overflow/Reservoir?

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
    Report

  • Re: 912 uls Blew out coolant

    by » 6 years ago

    Hello Bill

    I only had to refill the reservoir tank. The system itself was almost full still.
    It happened again this morning but only lost a cup full before I leveled off . I did replace a hose yesterday and maybe had some air stuck somewhere. I can't see anyway directions to bleed it>
    All gauges remained it the green.
    Thank you
      
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  • Re: 912 uls Blew out coolant

    by » 6 years ago

    It could just be that it just hasn't refilled itself yet.
    It should be 100% full.
    It will pull in more coolant during each cooling cycle.
    Manually fill the expansion tank 100% and half fill the overflow reserviour.
    If you replaced a hose it should resolve itself after a few heat/cool cycles.

    If it is leaking and it is not obvious, it could be leaking into the cylinder and out the exhaust.
    This is a common fault in cars but extremely unlikely in a Rotax unless there is a flaw in the head casting.
    The exhaust would be steaming, and the offending cylinder would have a steam cleaned sparkplug as evidence.
    I only add this thought in case all else fails. I would be surprised if this is the problem. So don't flame me, guys! :lol:

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
    Report

  • Re: 912 uls Blew out coolant

    by » 6 years ago

    Could it be your pressure cap is faulty and not maintaining correct pressure in the cooling system? A very low pressure would allow the coolant to boil, which would then blow steam into the overflow bottle and possibly push coolant out the vented cap.
    Thank you said by: Rob Seaton
      
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  • Re: 912 uls Blew out coolant

    by » 6 years ago

    It is definitely coming out the reservoir cap and spits out all over so I know it not a cylinder
    I ordered a new cap . If I baby it in the climb it doesn't do it at all only if I work it hard.

    Thanks guys

    On to the next issue my new tach starts blinking at some rpms and I have to reset. Plugs have about 30 hours but I am starting there.
      
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