Coolant leak

[Dorsal]

Anybody rebuilt one of these? you can see a little drool just over the spark plug. After a week the well at the base of the plug fills up, slow but annoying.

[Dave S]

Dorsal,

My plane/engine is pretty much the same vintage and model as yours including the 912ULS........on one or two of the fittings I get an occasional bead of moisture (coolant) showing up. There are two places where these leak...one is at the threads between the flange and pipe (which is sealed with threadlock) the second place is the O-ring between the flange and cylinder.

I don't think your experience is unheard of.......I don't get a pooling of coolant....just an occasional bead and no measureable loss @ the supply bottle.

I haven't fixed one of these; however, I believe Rotax shows the method in their maintenance method...It involves heating the joint with a propane torch to free up the threadlock (after removal from the cylinder) cleaning up the threads on both parts, renewing the threadlock with the specified k\material & using a new O-ring. Shouldn't be too complicated.

Sincerely,

Dave S
KF 7 Trigear
912ULS Warp Drive

St Paul, Mn

[Steves142]

Hi Dorsal, I replace 3 or 4 elbows when I installed my engine because they faced the wrong direction. They’re installed with the green loctite so it may be possible but hard to believe that the threads would start leaking and if they did it would be above the flange. My guess would be the o ring.

[Slyfox]

Dorsal,
something tells me that you should try heating up the screws and see if they tighten, even a little might stop that leak.

steve

[Dorsal]

All, thanks for the tips, agreed it is likely the o-ring not the threads. Will try tightening them first and see what happens.

[rockyrim]

Hey,
Mine came factory new missing one "O" ring, did the tightening thing for a little too long. Good luck.
Rocky

[Dorsal]

rocky, Good to know, will look for that. What was the result of tightening too long?

[Dorsal]

Replaced o-ring, will check after she has been sitting for a week and post results.

[Dorsal]

Just to close out this thread, no more leak after several weeks the area is consistently dry as a bone. In the end an easy fix, 1 hour start to finish and a $20 O-ring

[Dave S]

Dorsal,

Thanks for posting your results.....I can possibly see some O rings in my future now.

Dave S

KF7 Trigear
912ULS Warp Drive