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The 912 ULS installed in my RV12 has always tended to high oil temps particularly in the climb and worse on hot days.  For example =, on a 85-90 degree OAT the oil temp will be 240-250 climbing at 5200 rpm 85-80 kts  field elevation of 2660 to pattern altitude of 3660.

 

Checked oil cooler /cowl interface for air bypass.....no leaks

Checked oil lines for kinks....none

Checked oil level---mid flat spot on stick...using Shell Aerosport Plus 4

Finally checked the accuracy of the oil temp sensor/sender  part number 965531.

 

Tested the sensor with two calibrated thermometers three times and found the oil temp gauge on the Dynon D180 read 18 degrees high at 140 actual reading but  158 on dynon and at 235 actual dynon was reading 260, 25 degrees high.

 

I repeated test with another sensor from cylinder temp (they are interchangeable) and received same results.

 

Bought a NEW oil sensor, same Rotax part number, and found same spread...At 205 actual temp gauge read 225.

 

TAlked to Dynon and confirmed that the D180 was set correctly to sensor 4.

 

 So if your temps seem too high check the accuracy of your oil temp sensor.

 

It appears to me that the Dynon lapse rate is not programmed correctly for the rOTAX OIL SENSOR.

 

I an now going to buy a VDO oil sensor, test it and then if it is accurate install a stand alone Aviaspport Oil temp gauge.

 

 

Anyone else encounter this problem??

  • Re: 912 ULS OIL SENSOR inaccurate

    by » 3 years ago


    hi,having the same problem


  • Re: 912 ULS OIL SENSOR inaccurate

    by » 3 years ago


    I find these temps can be very normal at the 90F to 100F OAT. This can depend A LOT on air flow on each individual aircraft from different MFG's and even different individual builders. Hose routing and bends can make a difference and position of the oil cooler  into the in coming air flow. In the Tucson, Az area that I live in owners are always seeing 235F - 250F at take off and then it lowers once level. 240F - 245F is very normal here this time of year. Prop pitch can also make a difference. A tad too much pitch makes the engine work harder and that causes higher temps. What's you WOT rpm in level flight? I have found some oil hose in too tight a turn. I place a spring in them to keep them wide open and from pinching down and that tends to drop temps 15F - 20F.


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


  • Re: 912 ULS OIL SENSOR inaccurate

    by » 3 years ago


    I have the same problem. Mine is related to the current drawn by electric users. More users higher temps. Both cht and oil temp are effected. This can be solved by making your earth return path from engine to dynon thicker. Basically with all users switched off the temperature reading is correct!  


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