fbpx

 

Hello, I own a Rotax 912 Serial num 4152902, and have low oil pressure indicator at all RPM ranges; it always shows 1.5-1.8 Bar. I change instrument just to make sure the issue wasn't the instrument, and still shows the same. I changed the spring, and still shows the same. My gauge is the 0-10 bar VDO sensor.

Next week I plan on measuring the oil pressure using a classical gauge to connect directly instead of the VDO sensor to make sure the sensor is not the issue. So here comes my question: what can be the cause of a low oil pressure, if I don't have any oil leaks from the crank case nor hoses?

Thank you all for your help!

Loris

  • Re: Low oil pressure cause

    by » one month ago


    Does the Oil pressure go DOWN as the RPMs go UP?

    Check the Oil plumbing between the Oil TANK and the Oil PUMP for a kinked or Blocked hose. 


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


  • Re: Low oil pressure cause

    by » one month ago


    Hi Bill, thank you for your answer. The pressure does not go down when RPMs increase. I will check the hose between oil tank and pump as you suggested. Thank you


    Thank you said by: RotaxOwner Admin

  • Re: Low oil pressure cause

    by » one month ago


    I worded the answer to check the ""...Plumbing between the Oil TANK and the Oil PUMP..." because it is unlikely you will find a Single hose.

    Don't panic if you find 4 hoses, a Thermostat, and an Oil Cooler.

    They will all need to be ruled out.


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


    Thank you said by: RotaxOwner Admin

  • Re: Low oil pressure cause

    by » one month ago


    Hi Bill,

    I checked all the hoses, and have isolated the following components:

    • Oil tank
    • Oil hoses
    • Oil radiator
    • Oil pump
    • VDO sender
    • Oil pressure instrument in cockpit

    I made sure the oil did reach the pump. So the problem starts from there. The only remaining element to check and replace is the oil filter (although I understand the bypass wouldn't affect the oil pressure?).

    What is strange, is that I tried to push some oil in the engine (removing 1 spark plug per cylinder, connecting a hose straight to the pump entry line and turning the blades), but the oil would not get in... even after 30-40 blades.

    Do you have any clue of what else I could check? Is there a possibility the entry port on the engine block could be clogged?

    Thank you for your help!

    Loris


  • Re: Low oil pressure cause

    by » one month ago


    Describe in detail what you mean by "Checked all the Hoses".

    At 3000 rpm the oil pump will move all 4 liters of oil in under a minute.

    If the system can not flow a liter every 10 seconds at ~8 psi  you will have an Oil shortage.

    - - -

    Did you purge the Oil system after checking the input hoses?

    Hand cranking the prop to produce Oil pressure will be an aerobic exercise.

    You will need to pull at lease one blade per second.

    Cranking with Mags OFF should show Oil Pressure in under 5 seconds.

    If you have the spark plugs OUT,  No Oil will be returned to the Oil tank.

    Do NOT crank for more than 10 seconds with the plugs Out!

     

     


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


You do not have permissions to reply to this topic.