Using oil for the coolant system for a Rotax

[Kyle Communications]

I was talking with a friend of mine the other day and he tells me one of the flying schools sort of locally around here use "oil" in the cooling system on their Rotax powered training aircraft. I have never heard of this apparently the engines run 7 deg warmer but no electrolysis issues when doing this. The discussion started about what I am going to use in my Savannah I haven't decided yet but was probably going to use 50/50 water/glycol.

 

Never heard of using oil for that sort of cooling how common is this?

 

Mark

 

 

[fly_tornado]

My BMW R1150s are 65% oil cooled and 35% air cooled, so there is no reason why it won't work. contact the school and get some advice...

 

 

[facthunter]

Oil has nothing like the capacity to transfer heat compared with water. Brine is even better, but too corrosive to be used in engines. Glycol os not as good as water ( at transferring heat) but has a higher boiling and a lower freezing point. This permits the engine to operate at a higher temp without pressurising the system excessively.

 

I'm sure Rotax would not approve the use of oil as a coolant. There is a waterless coolant available that some use but the name of it eludes me at the moment.

 

Oil is used to cool some motors internally but not in the jackets. The Suzuki Katana and some BMW's to name a couple, but all motors to some extent rely on the oil to cool bearings, pistons etc. Nev

 

 

[Kyle Communications]

Thanks Nev

 

I thought it would have been a "off the wall" use but apparently it is used by this particular flying school

 

Mark

 

 

[facthunter]

Unless you have a freezing issue I would use Pure ( Non- ionic) water and a good corrosion inhibitor only. Glycol penetrates through the smallest crevises and doesn't inhibit corrosion. Nev

 

 

[Wayne T Mathews]

What does the manual say?... Has anyone asked Wal at Bert Flood's what he thinks of oil in the jacket?

 

 

[Guest Andys@coffs]

So I struggle to understand how this would be at all legal. If its a training aircraft (in Aus and within RAA) then it has to be 24 registered and operated IAW manufacturers instructions. I challenge to have someone show me POH or failing that in an engine manufacturers installation and usage manual, that will endorse this approach, and even if they can (engine manual) , unless the Aircraft manufacturer sends it to you that way from the factory then the point still stands doesnt it?........

 

Andy

 

 

[Kyle Communications]

Not too many freezing issues here in Qld...except if your out on the downs like Tomo....opps hope I haven't opened up another can of worms here Andy

 

Mark

 

 

[Wayne T Mathews]

I was talking with a friend of mine the other day and he tells me one of the flying schools sort of locally around here use "oil" in the cooling system on their Rotax powered training aircraft. I have never heard of this apparently the engines run 7 deg warmer but no electrolysis issues when doing this. The discussion started about what I am going to use in my Savannah I haven't decided yet but was probably going to use 50/50 water/glycol.Never heard of using oil for that sort of cooling how common is this?

Mark

There is a service instruction out from Rotax, Selection of suitable operating fluids, SI-912-016 R4, dated 31 AUG 11, and posted 14 SEP 11 on http://www.auf.asn.au/

 

 

[Guest Andys@coffs]

So, to use that tired old analogy "oils aint oils" Perhaps, after reading the link Wayne provided the "oil" that is being discussed is the waterless coolant which isnt an oil as such, rather, according to the document, "Propylene Glycol"

 

Andy

 

 

[Kyle Communications]

I will ask the question but I am sure it wasn't the propylene Glycol it was engine type oil

 

Mark

 

 

[Tomo]

Generally if oil gets in the cooling system of an agricultural, or motor vehicle it will run hotter. Oil retains heat much longer than water as Nev mentioned. (hence the reason they use it for cooking!)

 

 

[fly_tornado]

oil and water don't mix.

 

 

[Tomo]

oil and water don't mix.

Not generally, but they will if forced, just turns into a creamy mess.

 

 

[dazza 38]

Not generally, but they will if forced, just turns into a creamy mess.

I have seen that Tomo.In Diffs of 4WD's when they cross creeks and the water gets in through the diff breathers. Yucky mess.

 

 

[bushcaddy105]

Lots of info on American auto conversion websites. The coolant referred to is Evans waterless coolant. It is totally non-compatible with water -based coolants, and in my opinion, the jury is out as to its effectiveness and the need to use anything but water with an anti-freeze, antiboil additive. I have always used a good quality auto coolant concentrate, mixed 50-50 with clean rainwater out of a plastic tank. Good for 4 years before replacement.

 

 

[Yenn]

there is a lot of cooling done by the lubricating oil in aero and other engines. Especially air cooled engines, some of which spray oil into the base of the piston.

 

 

[RickH]

Perhaps the oil being refered to above is soluable oil and in the old days before the intro of the glycoltype coolants soluable oil was the usual in most water cooled engines

 

RickH

 

 

[Ultralights]

Dont forget, the Rotax 912 is about 40% oil cooled already! oil in the tank looses heat rapidly as well as the oil cooler itself, our savvy has the cooler about 1/3 covered in summer, and about 2/3 rds covered to maintain oil temp at around 95DegC.

 

the other coolant is Evans waterless coolant, though a similar product, well, its identical, glycol propylene or whatever it is, made for racing motorcycle engines, its far cheaper than evans.

 

 

[Sloper]

Goodaye all

 

Waterless coolents are the go.

 

http://www.evanscooling.com/

 

or

 

http://liquidintelligence115.com.au/

 

Not cheap but will last forever.

 

If you work through the sience of nucleation points it makes sense.

 

Its specified in my Viking.

 

regards Bruce

 

 

[dazza 38]

There is also a brand of coolant called Engine Ice. www.engineice.com. KTM used to recommend (maybe still do ) it in there KTM 990 Adventures as the run a little hot, up here in sunny Qld.It is kosher for different types of metals. Its expensive though I think.

 

 

[dazza 38]

I found a 2009 price for liquid intelligence 115. RRP was $35.95 per litre on the net. I might even buy some and put in my Motorbike.

 

 

[johnm]

 

 

I'm not much chop at web links but the above web refernce also has an excellent engine additive

 

JM

 

 

[Dieselten]

Evans NPG+ waterless coolant is specified for the Rotax 912/914 family. Rotax like it if you use no other.

 

 

[facthunter]

But none of these are oils. Oil will not remove heat anywhere near as well as water or the products mentioned. As well the hoses would not last long. IF you get even a small amount of oil in the coolant they deteriorate rapidly.

 

Any one who has done heat treating will know you get different results quenching in oil than with water or nitrate salts...Nev