Rotax 912 Best Coolant recommendation

[macedonranges]

I am confused about Rotax recommendations for Coolants for a 912ULS .

 

Some sites say use the Proplylene glycol waterless coolant others say to use the 50/50 water ethylene glycol coolant.

 

Appreciate recommendations>>

 

 

[Guest Maj Millard]

Either is approved by Rotax, the Castrol/Valvolene anti-freeze anti boil mixed 50/50 with demineralised water is easier to top up and source in most areas, especially remote areas. the Evans waterless cannot be ever topped up with anything other than Evans and its water content must never exceed 3.6 %. Also requires special flushing fluid if converting from Evans to regular coolant..................Maj....

 

 

[rankamateur]

Thanks Ross this question has been concerning me too.

 

 

[macedonranges]

Excellent Thanks Maj - that's great much appreciated and good thinking re if you need to top up while in the bush !

 

cheers

 

ROB

 

 

[Kyle Communications]

I use the castrol 50/50 and so far in 100 hrs of flying not a drama or a hot temp

 

 

[facthunter]

The Evans won't keep the engine quite as cool but is doesn't boil and form steam pockets and running a bit hotter (with safety) is actually a good thing for these engines. With water/glycol based mixes keep the water as pure as possible for corrosion protection. Running on pure water for short periods if you have to won't damage anything unless your venting with a cap pressure that is a bit low or flying at high altitude (lower boiling point due reduces pressure and freezing). Nev

 

 

[pmccarthy]

Rob,

 

Do you know which coolant is the blue stuff in the Texan ex dealer? I have never had to top it up but am coming up for the five year Rotax rubber change.

 

Thanks

 

 

[Keith Page]

As I see it the coolant chemistry is changing and this some of the teachings from the radiator shops. Organic additives are the way to go. In a nut shell the process of the coolant is to transfer the heat from the engine to the radiator which dissipates the heat hence coolants must go around and around and continue the process without failure.

 

Even in the mining industry coolants are evolving, for good reference points look at some of coolants as they must transfer great abundance of heat to the outside world. As yet I have not heard of any coolants failing, organics are there too.

 

As I see the subject we must do the new research as things have changed.

 

Regards

 

Keith Page.

 

 

[macedonranges]

Rob,Do you know which coolant is the blue stuff in the Texan ex dealer? I have never had to top it up but am coming up for the five year Rotax rubber change.

Thanks

Pete - I think that is an imported fluid - I am going to do a full flush off our system and change to the Castrol 50/50 solution.

 

 

[macedonranges]

As I see it the coolant chemistry is changing and this some of the teachings from the radiator shops. Organic additives are the way to go. In a nut shell the process of the coolant is to transfer the heat from the engine to the radiator which dissipates the heat hence coolants must go around and around and continue the process without failure.Even in the mining industry coolants are evolving, for good reference points look at some of coolants as they must transfer great abundance of heat to the outside world. As yet I have not heard of any coolants failing, organics are there too.

As I see the subject we must do the new research as things have changed.

 

Regards

 

Keith Page.

Hey Keith - yes I agree as new things are developed we need to look at these.. one thing I found today was the difference in prices with the Evans propylene glycol waterless being so much more expensive than the 50/50 water based ethylene glycol..

 

--- By the way anybody doing coolant changes be VERY careful that your pets never drinks the stuff as it is SWEET but will kill them very quickly from renal failure -- My Veterinary tip for the forum

 

 

[Keith Page]

You are correct coolants are dangerous as I was told good old Tech 50 was carsogenic even glycol is nasty for Mother Earth hence the reason for the organics they can decay in when back in earth.

 

Thank you for the pet tip. Just a thought could be good for rats and mice.

 

Regards

 

Keith Page.

 

 

[rankamateur]

Just a thought could be good for rats and mice.

Hope it killed the rats that completely ate the lower radiator hose off my header a few seasons ago!

 

 

[alf jessup]

I thought Rotax recommended the change to Evans waterless after they had some cases of the glycol/water mix evaporating off the water and boiling a few engines.

 

Best thing I ever did for my 80hp Rotax in the trike and my 100hp in the Tecnam, actually got the cylinder head temps up to 95 from the normal 70 they used to sit at.

 

Alf

 

 

[planesmaker]

I thought Rotax recommended the change to Evans waterless after they had some cases of the glycol/water mix evaporating off the water and boiling a few engines.Best thing I ever did for my 80hp Rotax in the trike and my 100hp in the Tecnam, actually got the cylinder head temps up to 95 from the normal 70 they used to sit at.

Alf

Alf if you take the water out of the glycol mix it boils at much higher temp. Straight glycol will boil at around 180'C I would suggest Evans would be up there too. Some setups have some marginal cooling and run close to the limits hence the reason rotax recommended Evans for those who maybe experiencing boiling. Tom

 

 

[Guest Maj Millard]

The Evans won't keep the engine quite as cool but is doesn't boil and form steam pockets and running a bit hotter (with safety) is actually a good thing for these engines. With water/glycol based mixes keep the water as pure as possible for corrosion protection. Running on pure water for short periods if you have to won't damage anything unless your venting with a cap pressure that is a bit low or flying at high altitude (lower boiling point due reduces pressure and freezing). Nev

My personal experience with the 912 is that they run too cool anyway most of the time, especially at cruise altitudes. I can't imagine why you would need a better coolant than the 50/50 Castrol Valvolene mix that I run in mine. Already operate with both oil and coolant cores 50% blanked just to say warm.......

 

 

 

[facthunter]

Your reasons (able to top up etc) are valid (for not running waterless although it is satisfactory in the 912 which does often run a bit cold) Ethylene Glycol does deteriorate over time to something a bit corrosive. Change coolants at periodic intervals as recommended with the product. It will rarely get dirty so if you are using the same one for refill I just drain and recharge the system. There are so many out there it can be confusing and mixing can be a problem, so avoid it to be safe. I've seen one go to gell...Proportions recommended should be adhered to, and using a weaker mixture is not advised. I think we are paying through the nose with some of the prices charged. What's new?? Nev

 

 

[Ultralights]

if you have a cap that doenst hold pressure too well, water will boil at a temp significantly lower than 100Deg C at altitude when not under pressure.

 

 

 

[Keith Page]

I am wondering if the 912 has an oil and coolant thermostat?

 

The thermostat has control of the operating temps.

 

Regards

 

Keith Page.

 

 

[Ultralights]

it depends on the installation, mine doesn't have either a coolant or oil thermostat. actually, i dont of any that do...

 

 

[Neil_S]

I thought Rotax recommended the change to Evans waterless after they had some cases of the glycol/water mix evaporating off the water and boiling a few engines.Best thing I ever did for my 80hp Rotax in the trike and my 100hp in the Tecnam, actually got the cylinder head temps up to 95 from the normal 70 they used to sit at.

Alf

Hi Alf,

 

I had also read that they then swung back to recommending the 50/50 glycol/water again.....We run the 50/50 in our 80hp 912A with no problem. I also bought a refractometer to check the ratio of glycol to water in the overflow bottle, and it does seem to indicate that the mixture will gradually acquire a slightly higher glycol ratio, (ie the water does gradually reduce), but I just top up occasionally with more 50/50 mix, or even a slightly higher distilled water ratio.

 

Cheers,

 

Neil

 

PS Agree wrt antifreeze and pets - my brother's cat died after drinking from a puddle of antifreeze/water under his car. Nasty stuff.

 

 

[facthunter]

A thermostat is something else to go wrong. In aviation simplicity is best.. Nev

 

 

[alf jessup]

Hi Alf,I had also read that they then swung back to recommending the 50/50 glycol/water again.....We run the 50/50 in our 80hp 912A with no problem. I also bought a refractometer to check the ratio of glycol to water in the overflow bottle, and it does seem to indicate that the mixture will gradually acquire a slightly higher glycol ratio, (ie the water does gradually reduce), but I just top up occasionally with more 50/50 mix, or even a slightly higher distilled water ratio.

 

Cheers,

 

Neil

 

PS Agree wrt antifreeze and pets - my brother's cat died after drinking from a puddle of antifreeze/water under his car. Nasty stuff.

Howdy Neil,

 

I haven't seen anything on Rotax recommending going back to glycol mix, I used the Evans in my 80hp trike for 5 years with no issues and now the Tecnam (100hp) for well over a year with no issues, wasn't happy with the glycol mix as the cyl temps ran quite low (75) on a 20-25 deg day, flushed the radiator with the Evan flush and filled radiator with Evans and got an instant 30deg rise in cyl temps now run at 95deg as recommended by Rotax (90+).

 

Took off one day from Yarrawonga to head back to West Sale via Mansfield & Licola Valleys loaded to max on a 37deg day, full noise climb to 9500agl indicated at 80 kts and the temps never got out of the top of the green (110) oil sat at the same 110.

 

I am far happier with the Evans but everyone has their choice, never once had to top up overflow bottle.

 

Cheers

 

Alf

 

 

[rankamateur]

I am far happier with the Evans but everyone has their choice, never once had to top up overflow bottle.Cheers

 

Alf

What is the service life of the Evans coolant Alf?

 

 

[macedonranges]

Wow great replies and thanks to everyone for their input.. its all part of the learning curve and maintaining the plane the best possible way.

 

 

 

[alf jessup]

What is the service life of the Evans coolant Alf?

rankamature,

 

Going by the website you never need to change it in the lifetime of the engine so it seems good value.

 

Alf