I am a new owner / mechanic of my RV12 with the Rotax 912is engine.

I have noticed a coolant leak / weep directly below the water pump on my new 912is.  To better define this leak it appears to have one or two droplets at the bottom of the water pump.  Some of this coolant gets spayed onto the firewall during flight and a very small amount (small droplets) are detected on the bottom cowl.  No fluid drips onto the hangar floor as I only noticed when I removed the lower cowl after about 15 hours on the engine.

Is this something that I have to be concerned about?

Minimal coolant loss is detected in the expansion bottle; not much has changed in 15 hrs.

Any input is appreciated.


Rich Pezzullo

  • Re: 912is water pump leak / weep

    by » one month ago

    Hi Rich,

    This can be very normal especially in cold weather. There are different materials in the pump that will expand and contract at different rates so a drip occasionally in cold weather is normal. For some that may go away during the hotter months. Even then during inspections I may see a drop hanging off the bottom of the pump, but no real leak. If you have a few drops to a tablespoon type thing no big deal during the cold periods, but if you have a big puddle that's a different story.

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

    Thank you said by: James N Parker

  • Re: 912is water pump leak / weep

    by » one month ago


    Thanks for the prompt reply and valuable information.


You do not have permissions to reply to this topic.