High Cht

Category: 912 / 914 Technical Questions 8 months ago

Hello Guys,

New plane and new problem I have a 2005 Fantasy air allegro 2000 with a 912 80hp with 300 hrs , i just finish replacing all the coolant hose  flew the plane several times and topped off the coolant to get all the air out today I flew it for about 30 min and the cht was solid at 220F then all of  sudden it shot up I throttle back and land with in a minute throughout alll this the oil temp stood normal in the green when I took of the cowling I notice that the coolant reservoir was completely empty  before taking off it was full in the last week I replace the temp gauge and sending unit (vdo) What else can it be? How can I see if the water pump is working properly ? I'm using 50/50 dexcol

  • Re: High Cht

    by » 7 months ago

    It sounds like some coolant was lost. Did one of the new hoses come off or did it escape past the pressure cap? If you have a coolant escape in flight you can usually smell the additive in the cockpit. If coolant gets past the pressure cap then you should see excess coolant in the overflow tank.

  • Re: High Cht

    by » 7 months ago

    If any hose To/From the water pump gets warm as the engine warms up, the pump is moving coolant.

    If you had a leak you will have oily coolant in the vicinity of the leak and probably enough sprayed around that it would drip from the cowling after landing.

    Do you have a hot water cabin heater core that my not have been purged?


    When you say the "Reservior" was empty I assume you meant the Overflow Bottle.

    When you looked under the Pressure Cap on the Expansion Tank, was it empty also?


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

  • Re: High Cht

    by » 7 months ago

    Hey Guys Thank You for the Response,

    I found out what was the Problem, I had a bad Cht Sender also had the radiator flush and pressure cleaned. I have flown 2 hrs already with the temps in the Green. One of my Radiator hose came loose thats why I lost all the coolant. 

    Thank you said by: RotaxOwner Admin

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