How common are 912 water pump failures.& cause?

Re: How common are 912 water pump failures.& cause?

by Al C » 12 years ago

Al C

63 138 106

Hi Rodger,

You wrote, in part --
"sometimes through heating and cooling cycles or when it is really cold outside the seal may ooze. If you see a tablespoon or so on the ground of coolant that isn't a sign the seal is bad. It may be the temp change ...."

Interesting that you wrote that:

Last week we had and unseasonably cold night (for us in southern Oregon anyway) down to 0-degrees F. Had flown the plane the day before.
Two days later came in to fly and noted about less than 1/4th of a teaspoon of coolant on the floor.
Cancelled the flight and spent at least an hour carefully checking for where it could've leaked from. Checked all reachable coolant hose clamps, none loose. Never found any source of coolant drip. (Did find one oil hose clamp a dad loose with tiny seepage, tighter it. Good reminder to peek under cowl more often.) Carefully cleaned everything under cowl of all traces of anything fluid.
Put sheets of clean paper all around to check for more leaks. Ran up engine on ground for 12 minutes. Couldn't detect any leakage. Flew plane. Looked under cowl for coolant leak. None apparent. Parked plane over the paper. Came back next days and found one or two drops of coolant(and I mean just drops like from an eye dropper.) Those appeared to be "leftovers" from the earler tiny leak that I missed cleaning off some hidden bracket or something. Never did find any leak as such.

So your report that this is common (didn't really know about the weep hole... wouldn't know how to find it) is reassuring.

BTW, our 912UL has about 650 hour and 13 years on it and by all other measures (leakdown compression, etc, etc.) is in prime condition.

Al

Re: How common are 912 water pump failures.& cause?

by Roger Lee » 12 years ago

Roger Lee

131 5.38k 5.44k

Hi Al,

Glad it was timely. The weep hole is on the bottom of the water pump housing on the back of the engine (if you have a tractor prop).

---

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

Re: How common are 912 water pump failures.& cause?

by CLEMENT BRETON » 8 years ago

CLEMENT BRETON

1 2 1

why rotax made new impeller with two holes ? reason ?

Re: How common are 912 water pump failures.& cause?

by Rob Seaton » 8 years ago

Rob Seaton

3 1.32k 251

the holes help prevent cavitation behind the impeller.

Re: How common are 912 water pump failures.& cause?

by CLEMENT BRETON » 8 years ago

CLEMENT BRETON

1 2 1

Ok, thank you very much, Rob