Trike Maintenance and Resources

Trike Maintenance and Resources

Oil Pressure Sender problem on Rotax 912 series engines?

Last updated by XC Triker Comments (10)

Categories: Trike Talk, Equipment, Maintenance

Is anyone else having failures of their Oil Pressure sender frequently?  I've gone through about 4, this last one lasted about 3 months only.

VDO Oil Pressure sender

 

From what I know this is a known reliability issue.  Sometimes they last a while and sometimes they don't.  The failure is thought to be due to vibration (my engine has been balanced, yet no improvement in reliability of sender).  Rotax now ships their engines with a much more expensive sender made by Honeywell (if I remember right it's around $300 and has different electronics, so hooks up to your gauges differently/requires different gauges).  The Rotax part appears to be the exact same as the VDO part, just rebranded and more expensive.  The Rotax version does have a brass weighted ring on it that will slip off the Rotax part and directly onto the VDO sender (so no apparent difference at all in the end)(the weight is supposed to reduce the vibration frequency).  Another proposed solution is use of a "remote" unit- wherein the oil pressure sender (which usually bolts directly into the engine on left rear (opposite the oil filter)) instead of being directly connected is connected instead by a length of flexible hose.  This theoretically will reduce the vibration of the sender-  however in my mind it adds a hose that if it leaks would lose all your oil/pressure in short order.

My first & second VDO style oil pressure sender lasted a long time, so I figured it cheaper & easier to replace with the same at $35 versus ~$?300.  However, now I'm second guessing that.

I need help from you guys as to what you're seeing, what you recommend, and any thoughts.

The first time my oil pressure read zero and alarms went off on my dash and in my head-- but I realized soon it was not real and gingerly flew the 7 miles home.  Still, I'd just rather avoid this issue.

 

Comments

  • jeff trike

    No problem with mine, and it has 1100 hrs and 7 years on it.

    Jeff

  • XC Triker

    This topic has been split to THIS THREAD

  • Ttabs

    My nemesis is the fuel pressure sending unit. Have had no issues with oil p on two motors now. I'd keep trying the cheap ones.

  • XC Triker

    Hey @Ttabs, that's what I thought too, but this last one I replaced in your hangar before Elk River (barely 3 months ago)-  it crapped out a couple days before I left for up there and I had to have it overnighted to @GeoBlaze 's.  I've gotta get Matt's / MGL's word on whether the Honeywell is a straight swap, or I have to mess with the gauge / Enigma and how expensive / complicated that is.

  • XC Triker

    Hey cool, I just got this email from @Karl (maybe this will help defray the cost & help out Karl) : 
    Don't buy anything yet. When I first bought my trike from Bill we were chasing a mysterious oil leak at the back of my engine. He bought a new sender from Rotax for like $275. We changed it out and it didn't help. The leak ended up being my fuel pump at the pushrod seal. I will find it today and send you a pic. If you want to put it on I will ship it up to you.
     
    Karl

  • XC Triker

    Still working on this question.  Put some calls out.  Does anyone think differences in reliability engine to engine may be due to the "installer's" technique (wrong torque for example)?

    @Ttabs are you back to the fuel pressure sender as the root of your problem again?

  • Ken

    Have you talked to Lockwood?

  • TrikeCFI

    Here is something I got from Lockwod on this isue a while ago,

     

  • TrikeCFI

    Most of my 912 oil presure sender issues have been with low pressure readings which were bad sender electrical connections reading 0 presure. The most recent oil pressure problems were with an O-200 bad wire connection reading over pressure from loose wire/bad connection. Sometimes hard what to believe and assess the situation.

  • XC Triker

    I called Lockwood, but forgot they only take tech questions between 9-10am & 2-3pm Eastern, so ...  But, Matt from MGL said this (good news on the switch (except the cost)):

    Thanks for the call.
     
    Yea, you can switch to the Honeywell. You just have to add a 100 ohm resistor and change settings like this:
     
    http://kb.mglavionics.com/article/AA-00244/7/EFIS/Connecting-the-New-Style-Rotax-912-Oil-Pressure-Sensor-to-the-EFIS.html
     
    Best,  Matt

    TrikeCFI, that's a very timely video for a couple questions I had, thank you!  When was that dated?  I just switched from Mobil 1 to Aeroshell sport Plus 4--  Much harder to find and more $$, but I run Avgas on long trips if I have to.  Matt's explanation plus Lockwood's adds more detail to the sensor change-out--  I can pick up a 100 ohm resistor quick & easy at Radioshack.  Then pay my $300 to Honeywell ... :(