fbpx

 

We changed the oil and the filter in our 912 80hp and after start up the oil pressure gauge is reading zero . We killed the engine and everything checked .....plenty of oil and the oil pressure sending unit appears to be all connected properly . We have been flying the plane regularly and honestly I don't know if the gauge has been working ..........I just haven't noticed . While on the last flight the engine performed well and the water temp was in the green right before we changed the oil . 

  I am tomorrow going to get out my voltage and ohm meter and see if the oil pressure sending unit is getting voltage and ohm the gauge and see if it is OK .....perhaps a broken wire ?..  I will report back my findings .

The question is : Is there a lag on getting oil pressure to the gauge or pressure unit on the block ? My friend ran the engine 3 minutes and no pressure showing on the oil pressure gauge (which is electric) ............We checked the oil dip stick and no metal shavings shows up AND the oil that came out of the engine during the oil change didn't have any silver flakes . aka metal . I hope it is a faulty gauge . I have never had an engine take 3 minutes to get oil pressure after a change . Give me some thoughts on this please ........Thanks , Mike  

  • Re: Rotax 912 80hp no oil pressure after oil change

    by » 2 weeks ago


    I like to do a full oil/air purge, every time I change my oil/filter. May not be necessary but it gives me piece of mind, that there is no air in the system that may be restricting circulation.


  • Re: Rotax 912 80hp no oil pressure after oil change

    by » 2 weeks ago


    Hi Mike,

    Yes you should have had oil pressure. For the moment this doesn’t sound like a real oil pressure issue. If I have something like this or a weird gauge reading I put on a separate mechanical gauge to compare. You can go to the hardware store and buy a brass fitting to install down at the oil inlet at the pump. Then I run a small copper flexible tube up to the top of the engine. Small inside diameter tube.  Then I put  a tee fitting in line there. Here I hook up the original panel instrument hose and on the other tee fitting side a mechanical gauge. I leave the mechanical gauge slightly lose at start until I get a couple drips of oil to make sure my line is purged of air then tighten it.  Nw I get to compare readings. I’ve never had a real oil pressure issue. It’s usually the sending unit or the panel gauge or a bad wire.

    This test is only for a ground run to test the system.


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


    Thank you said by: Sean Griffin

  • Re: Rotax 912 80hp no oil pressure after oil change

    by » 2 weeks ago


    Hi Sean,

    During an oil change you should have very little air introduction. This isn’t an issue. Plus I highly recommend

    pre-filling the oil filter. I can fill an oil filter three times to the top and it won’t spill any on installation. The oil soaks into the filter medium and out into the outer part of the canister.  If you’re worried about air then just do a venting by rotating the prop to help charge the filter more. A NORMAL oil change should not introduce enough air to require a full oil purging. The engine can handle a small amount of air.

    Oil venting and an oil purge are different for those who don’t know.


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


    Thank you said by: Sean Griffin

  • Re: Rotax 912 80hp no oil pressure after oil change

    by » 2 weeks ago


    My oil pressue comes up almost immediately when the engine starts. My starting checklist says to shut down the engine if no pressure is seen within 10 seconds. If it ran for 3 minutes with no indicated pressure and the engine sounded normal then I suspect you have a gauge or sender issue that you will discover with your multimeter. You could just unscrew the valve, leave it connected to the gauge, add a ground wire and pressurise it with a foot pump. You can then fault-find it from there.


  • Re: Rotax 912 80hp no oil pressure after oil change

    by » 2 weeks ago


    Or install a wet line panel oil pressure gauge fed by a braided steel hose wrapped in fire sleeve (Down Sean! Down! Bad Sean! Bad!) 😀 and never worry about sending units or grounds or fabricating test wet lines or electrical anything ever again.  


    Thank you said by: Sean Griffin

You do not have permissions to reply to this topic.