We live in the hot desert here in Las Vegas. Typically our oil temp runs close to the 250 mark in the summer. All of a sudden it has shot up to 280 deg. (Red Line) but all other indications are normal. The CHT is running cool at 205 deg., All EGT's is below 1000 which is well within the green, Oil pressure is at 57 #, I replaced the transducer with the same results. I am thinking that it may be the Dynon D-1000 EFIS reading wrong. I do have an oil thermostat installed and that is the only other thing that I can think of that may be the problem.

Please let me know what you think and any hints on how to troubleshoot the problem would be appreciated.


  • Re: 912 ULS Red Line Oil Temp

    by » 8 months ago

    If it is easy to remove the stat then I would try that in case it is bypassing the oil cooler. Could any of the oil hoses be reducing in internal diameter if they are getting too hot? As the rubber hoses age, they naturally get softer and this becomes more likely. Look at areas where they are tight bends, particularly if they run next to something hot.

    Let us know what you find.

  • Re: 912 ULS Red Line Oil Temp

    by » 8 months ago

    I have had to replace 1-2 thermostats over the years, but it's pretty rare. Oil hose in too tight a bend squeeze down and reduce flow and that will cause increased heat. When I have an aircraft Mfg with a bad bend I install a spring in the hose to maintain its wide open status. I have seen many temps go down 15F-20F by doing this.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

  • Re: 912 ULS Red Line Oil Temp

    by » 7 months ago

    Problem solved! The oil Thermostat was the culprit. Thanks for all the help.

    You guys rock!

    Thank you said by: RotaxOwner Admin

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