Hi , I have some problems with the oil press sensor keller. After 100 hour on the engine it no longer works. I tried everything from cables to instrument and all work ok. It is possible that it broke in 100 hr of use ?

Its a very expensive engine to have this kind of problems, In 100 hr I have change 2 times the carburators floats. This last time I have to pay for them and its crazy , more than 300 dolars for them.!!!

and now this problem with the sender.....

please help me to understand these crazy things !!!

  • Re: Oil pressure sensor

    by » 8 months ago

    Dear Alejandro,

    I have one of the first 912UL's that were built and am chasing down oil pressure and oil temperature issues, too. In my case, the temp sensor is a VDO type that Rotax no longer uses so I have been waiting 4 weeks to get one from a Marine Supply Store! I changed out the VDO oil pressure sensor last week and started getting readings in the green (down from yellow) so I hope I replaced a bad sensor with a good one... The only other thing I did was change the oil and filter.

    I think it comes down to the fact that this is a relatively complex engine designed to elicit the most horsepower from the lightest weight. Direct drive aircraft engines are simpler in many regards but can't match the power-to-weight ratio and so you have to deal with the complexity. Rotax chose to use the "dry sump" method for lubrication and thus we have all those extra hoses. A dry sump allows the motor to have less vertical height and potentially be mounted lower than an equivalent wet sump motor. A dry sump system typically has more oil to circulate than a wet sump so that can be an advantage, also.

    Regardless, all gas engines have oil pressure and temperature readings and it seems that the vendors Rotax has chosen for its sensors could "up" their quality control. I have been reading lots of posts in rotax-owner about these sensor issues and you and I are not The Lone Rangers.

    Perhaps someone at Rotax who monitors these posts would be willing to comment on this.

    Viva Argentina!

    Brian FitzGerald - The Sky Surfer - Kansas

  • Re: Oil pressure sensor

    by » 8 months ago

    It's not just Rotax. Cessna, Cirrus and Piper with their Continental and Lycoming engines along with solid state electronic sensors also have a shorter sensor life. They just can't take the heat and vibration long term. Consider remote mounting the sensors, there are kits available at Aircraft Spruce to do this. The older model aircraft out there still have capillary tubes that feed temperature and oil pressure that are still working after decades in service.



  • Re: Oil pressure sensor

    by » 8 months ago

    Brian thank you for Your support.

    Its nice to know that Im not the only one.....

    I hope that someone from rotax read the topics   .

    As you said, vendors are not as good as the engine concept and design .

    Imagine in Your car changing sensors every 10000 km !!!!!!

  • Re: Oil pressure sensor

    by » 8 months ago

    To save $ on sensor replacement once you know the sensor type/functionality and scaling you can usually find a replacement/Chinese knockoff on eBay  for a 10th of the cost.

  • Re: Oil pressure sensor

    by » 6 months ago

    Ran across this thread an thought I would add my 2 cents worth on this topic.  I purchased an RV12 with a Rotax 912UL with 144 TO.  30 hours into flying the plane I lost oil pressure. Trouble shooting lead me to replacing the oil pressure sensor.  The history of 912 oil sensors, the VDO is the oldest, then the Honeywell and now a newer type.  You have to be careful with the Honeywell because it is a NPT thread the new one is not.  So I had to replace the oil pump housing, yikes that was expensive.  Got it all replaced, competed the oil purgeing procedure and all appear fine.  However after 20 hours of flying I notice a clicking from the left cylinder and sure enough after checking some air apparently has worked its way into intake lifter in that cylinder.  I am having a hard time getting it to purge.

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