912ul water pump leak

[Dorsal]

I agree with Dave S as I have had to chase down a number of small leaks over the years. Causes for mine included thread sealant on a pump fitting, o-rings on the cylinder fitting and the hose connections as they got older. The origin of the leaks was usually pretty difficult to detect initially appearing as a drip on the bottom of the engine.

[HighWing]

Years ago, I had a small leak - can't remember where exactly - and called Rotax. I was told to use Bars Leak at a smaller quantity due to the relatively smaller coolant volume in our engines. After that I flew another 600 hours to finish out the 900 hours total. All with it in the coolant with no further drips or other issues. Curious about the urgency of the flushing recommdations. Is this per Rotax?

[Xengineguy]

Years ago, I had a small leak - can't remember where exactly - and called Rotax. I was told to use Bars Leak at a smaller quantity due to the relatively smaller coolant volume in our engines. After that I flew another 600 hours to finish out the 900 hours total. All with it in the coolant with no further drips or other issues. Curious about the urgency of the flushing recommdations. Is this per Rotax?

Stop leak seems to settle out and end up in the inlet tanks of heater cores and
Radiators. (I have disassembled hundreds of heater cores and radiators in the
Last 25/30 years of business.I recore and repair radiators 5 days a week). Given the size of the heat exchangers we use
We don't have a lot of margin on the liquid side of the system.Plugging
Just 9 tubes could be more than 10%???. Don't tell anyone but black pepper
Is probably the best stop leak!

[HighWing]

Don't tell anyone but black pepper
Is probably the best stop leak!

Sad to hear. It just might force me to share my black pepper with the airplane. Just love the stuff on everything.

Seriously, Thanks for the experience heads-up. I can go with that. Still, I wonder if it might have to do with the amount added. In the day, Rotax was very firm on the amount added because of our relatively small coolant capacity. It was just a fraction of the bottle. I had shutters on the radiator and still used them regularly up until the end.

[Xengineguy]

Sad to hear. It just might force me to share my black pepper with the airplane. Just love the stuff on everything.

Seriously, Thanks for the experience heads-up. I can go with that. Still, I wonder if it might have to do with the amount added. In the day, Rotax was very firm on the amount added because of our relatively small coolant capacity. It was just a fraction of the bottle. I had shutters on the radiator and still used them regularly up until the end.

Lowell I think you have a good point, unlike most people you followed the
Rotax instructions. Too often we think if a little will do,a bunch is better!
Not the case with this stuff. Mike