Benefits of Evans cooling media

by Jean-Paul Koeune in General Tech Discussion 13 years ago

I wanted to know what would be the benefits to switch to that type of coolant. I do have a 912s... Thanks

Re: Benefits of Evans cooling media

by Roger Lee » 13 years ago

Roger Lee

128 5.28k 4.98k

Hi Jean-Paul,

There is a few things to consider before the change. First of all do you need it? Are you constantly boiling over? There are other ways to bring the temps down on an engine if it is over heating. For many it is just unloading the engine by reducing prop pitch. The 50-50 anti freeze boils at 270F. That was too close for Rotax's 266F max on the 912ULS and it might hit its boil point in a hot spot and turn to vapor in certain areas and then you would loose its cooling there and possibly have metal fatigue. So Rotax reduced the 266F when using 50-50 to 248F to give a little safety margin.

If you use Evans its boil point is 370F, but it raises CHT's, coolant temps about 25F and up to 30F and for many that takes them over the max Rotax temps anyway. The Evans has no water so it doesn't heat transfer as well as water based coolant. If you have an open air engine you will most likely be okay with Evans, but I have found aircraft with a tight cowled engine or one up close to the higher temps to over heat and then Evans becomes counter productive. Evans is a good coolant, but not for everyone. I would hazard a guess most 912 users still use 50-50 coolant. The other item with Evans is if you ever have to add coolant because the level dropped then it must be Evans and if you're away from home that is problematic. With 50-50 you can add a compatible 50-50 or distilled water.

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

Thank you said by: Jean-Paul Koeune

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Benefits of Evans cooling media

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