Evans Waterless Coolant for Rotax 912 Engine

[DavePA11]

Did anyone try the Evans waterless coolant in a Rotax 912 engine with their gyro? I have a Sportcopter M912 and replacing a leaky radiator so considering switching from standard silicate-free coolant to the Evans waterless coolant. Evans has much higher boiling temperature so it will not boil thus does not build up pressure as the 50/50 mix coolant does.

Here is the Rotax link covering the coolant system and recommended coolants:

https://www.rotax-owner.com/pdf/ROAN cooling.pdf

Thanks,

Dave

 

[Smack]

I've been using Honda coolant (straight) for about 10 years and have had no issues.
Brian

 

[Uncle Willie]

Rotax has changed their thinking since first recommending Waterless coolants.
It is no longer approved for use in the 912i series engines or any engine with the new -01 Cylinder heads.
It also has a lower Specific Heat Capacity so if your engine is already running hot, it is going to run even hotter with the waterless coolant.

SI-912i-001r3.pdf
https://legacy.rotaxowner.com/si_tb_i...912i-001r3.pdf

 

[DavePA11]

I'll stay with the silicate free coolant then. Thanks!

 

[Cammie Patch]

I'm doing coolant hose change right now on a CTSW, and I'm tired of the smell of the Evan's coolant! It will run hotter, but won't cavitate (form air pockets) until a higher temperature. Even so, I don't recommend it, it's more difficult to find, and you can't add water to it in a pinch.
Be sure to use Dexcool. Silicates can be very bad for a rotax. I wouldn't even use DC-4 on an oil filter gasket for that reason.

 

[Steven]

Dave, on your Sport Copter installation the cooling system is so efficient that the factory has installed a radiator attachment to block off most of the airflow (it's adjustable) as the engine runs too cool even on the hottest of days. So for you, the advantages of the Evans coolant would far outweigh any negatives. As it stands, Rotax still recommends Evans for your particular engine. There are advantages to running low or zero pressure in the coolant system, such as being kinder to the seals and possibly helping with any present leak issues.

Evans is silicate free and far less corrosive than any standard cooling mix that requires water. Then there's the blessing of never having to change it.

You're unlikely to travel much of a distance in the Vortex so worrying about adding a few drops is probably not much of an issue.
I've been using it for years and wouldn't consider anything else.
Steven

 

[DavePA11]

I ended up using DexCool. Evans was on back order at Amazon, and I wanted to go flying. Yes, the Vortax M912 with the big radiator can run cool without adjusting the louvers properly.

Thanks for all the replies!