Evans waterless coolant

[Harvey rv12]

I have Evans waterless coolant running in my Rotax RV-12. I have read that it runs somewhat hotter than glycol water based coolant. has anyone switched between the 2, and noted what kind of CHT difference results ?.
My CHT's are often bumping around the 230 deg mark, and I am wondering how much cooler it might run with conventional coolant.

Tom O.

[Bill_H]

Search this forum using the word "Evans." Several interesting and related threads. Why are you using Evans?

[Harvey rv12]

The Evans was installed on my plane when I purchased it. not sure whether or not to change to conventional.

am searching posts now.

thx

[simpkinsona]

I'm using Evans coolant in my Subaru powered RV-9a. Some Subie users have switched to try to improve cooling but I don't know of any back to back testing. Personally I think there won't be much difference. The nice thing about the Evans is you can run as low as zero on the cooling system pressure and the boiling point is over 300 degrees. Also Evans is supposed to be better on corrosion resistance, and lasts indefinitely.

-Andy

[bajapilot]

I've had some experience with in on my Rans, haven't used it in my 12. Evans does run hotter, usually 10 degrees or so, it has a higher boiling point but doesn't transfer heat as well as glycol. You will run hotter with it, you don't have to worry about boiling but remember this will also raise your oil temp somewhat, something most of us hot weather flyers don't want.

Most everyone I know in the Rans community has switched back to glycol because we tend to fly into the back country where water is available and Evans is not. The two are totally incompatible so you can't add water is you have a leak.

Bill

[RFSchaller]

I decided to run water and antifreeze in case I need to add coolant on the road. I figure water will always be available.

[Sink]

Hi Harvey,

Depending a little on your engine setup (i.e. open air engine versus closed cowl) Evans carries a 20F-30F temp penalty. Rotax doesn't recommend it any more. If your CHT's are 230F then this is a little hot for CHT's. Mine are 205F. I would think your oil temp would be up a tad high too. CHT's normally are approximately 15F-20F below the oil temp. This can vary slightly between engine and aircraft setups. As the guys mentioned water is easy to come by if you need to add and Evans isn't. Water does a much better job off heat adsorption and absorption. This is why fire department use it. It's the best inexpensive heat adsorbing coolant for heat (fire) out there.

[rv6ejguy]

I ran Evans for about 5 years. Switched back to conventional and my temps dropped about 18F. Wouldn't go back to it again. The coolant might be good for 300F but your engine will probably seize or be damaged way before that happens so that part is of dubious benefit. If your coolant temps are high, best fix the problem properly with a better rad setup.

[BillL]

Originally Posted by rv6ejguy

I ran Evans for about 5 years. Switched back to conventional and my temps dropped about 18F. Wouldn't go back to it again. The coolant might be good for 300F but your engine will probably seize or be damaged way before that happens so that part is of dubious benefit. If your coolant temps are high, best fix the problem properly with a better rad setup.

+1 Absolutely - you may be able to tolerate higher cooling temps, but lubricant capabilities have increased little (if at all for available oils) in half a century. Remember oil keeps the engine running.

[Harvey rv12]

Interestingly my CHT's are a little higher than my oil temp.
Based on what I'm hearing I am going to drain the Evans coolant and
Go with the dex/ glycol mix. Sounds like 10-30 deg reduction is possible.
Is there a thermostat in the 912?

Thx for the guidance
Tom O.