912ULS High CHT. can't determine why

Re: 912ULS High CHT. can't determine why

by WARREN ROBERTS » 10 years ago

WARREN ROBERTS

4 5 0

Unless I'm mistaken doesnt the rotax operating manual indicate an allowable cht of 300 farenheit?
you guys are way more sophisticated than I am but I was having a similiar overheating problem and it was an airflow
cooling problem....not sufficent airflow over the cylinders. ...

Re: 912ULS High CHT. can't determine why

by WARREN ROBERTS » 10 years ago

WARREN ROBERTS

4 5 0

Radiator I meant

Re: 912ULS High CHT. can't determine why

by Zach Holderfield » 10 years ago

Zach Holderfield

2 5 0

Well, I still have no resolve with this and my local Rotax mechanic is baffled. I have flown 6 hours in the pattern and CHTs are still consistently around 255F. I landed and took cowl off and used an infrared thermometer to check each cylinder head temp and compare with the temp indicated on the Dynon. The temps were all around 245 and dynon displayed the same temp. The coolant expansion temp was around 233F. The only thing I know that is left to check is the impeller/water pump but from my reading they basically never fail. Oil temps are still running around 210-215, ambient temps have been in the 80s over last few weeks. if anyone has any other ideas that I am missed please let me know.

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Re: 912ULS High CHT. can't determine why

by tom oatman » 10 years ago

tom oatman

5 28 0

Dumb question, but are using evans waterless coolant?, I was using that in my rv-12 with 912uls and my CHT's were 235-240. I flushed and refilled with dex-cool coolant, and my temps dropped 30 degrees.

Tom O.

Re: 912ULS High CHT. can't determine why

by Andres Montoya » 9 years ago

Andres Montoya

4 2 2

Hello,
Hope anyone can help...
In the last 3 flights (1 hour each), during taxi and engine test (no more than 5 minutos From engine start) the right CHT on my 912 ULS with 150 hours rise to the maximum limit, then power for takeoff and goes normal.
Thank you for any suggestion.