Can we mix orange and green antifreeze?

[tennesseect]

Is it permissible to mix orange and green antifreeze?  I see Rotax has approved several types but can I just buy by color at the auto parts store?

[GrassStripFlyBoy]

Walmart has Dexcool on the shelf, I don't care for "universal / equivalent" type products, spend a few bucks more and buy the name brand.  Probably ok using the generic stuff, but to Roger's point so little is needed it's not a big deal.

[AGLyme]

FD USA recommended to me the blue BMW motorcycle coolant. Found at BMW motorcycle dealers.

[AGLyme]

3 hours ago, Roger Lee said:

Rotax says use a 50/50 mix

Right, 50/50 with the BMW coolant.  I had to drive 45 minutes to get it.  Whatever works and certainly you would know.  Given the Tucson temps, you have a very good idea of which coolant works.

[MEH]

Be careful if you are intending to add anything to "Blue" coolant!  You should read the Rotax Fluids Service Instruction that was just revised (attachedRotax fluids service instruction.pdf).  According to Rotax, the blue stuff should be "Waterless Coolant" aka Evans in the USA and Aero Cool 180 in Europe.  You should never add water or water based coolants (green or orange) to the waterless blue stuff. See the Rotax Service Instruction.

[Tom Baker]

On 12/12/2020 at 12:36 PM, tennesseect said:

Is it permissible to mix orange and green antifreeze?  I see Rotax has approved several types but can I just buy by color at the auto parts store?

Your airplane has Dexcool 50/50 pre mix in it.

[AGLyme]

MEH,

My blue BMW motorcycle coolant is mixed 1:1 with distilled water as per FD USA... I run a 912i... I believe the Rotax manual supports FD’s recommendation.  Thanks for sending the Rotax info.

[MEH]

My apologies.  The waterless Evans (in the blue jug) approved by Rotax, is not to be confused with the 50/50 BMW blue stuff approved by FD. 

[AGLyme]

No worries, it was a good exercise on coolant.  Glad you posted the manual reference.

[FlyingMonkey]

I was planning to change out the Dexcool this annual, but if it's rated to five years...

[Tom Baker]

I normally only change during a hose replacement, unless I have the cooling system open for some other reason.