Using oil for the coolant system for a Rotax

[turboplanner]

As someone who had to tell trucking companies in the 1980's that they were not going to get a few million dollars warranty because they disregarded the coolant instructions which were ABSOLUTELY CRITICAL to getting any sort of life out of the liners, I find this thread dumbfounding!

 

The engine designer will have tested and specified a coolant mix to give a reasonable liner life without pinholes. DON'T EVEN THINK ABOUT USING ANYTHING ELSE.

 

You can of course, but expect pin holes and rebarrelling if you like engine rebuilding.

 

The problem is caused by the more efficient dissimilar metals we've used for the last 30 years, the downside being you have to use the correct coolant - in your 20 year old Japanese cars as well unless you want to spend a couple of grand every 18 months or so.

 

 

[alf jessup]

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

I think the reason rotax advised it's users for this Evans NPG is they had some reports of some engines overheating due to evaporation of the water in the 50/50 type mixes.

 

Most likely due to pilots of those never checking the coolant levels ever. (my assumption)

 

I noted with the Evans that i got about a 10 deg increase in running temp which is great for the southern states of Australia during winter.

 

Be aware that if you do decided to use it you also have to buy the Evans flush also to flush all the water/glycol mix out of the cooling system.

 

I've been using it for 4 odd years and have no complaints.

 

Alf

 

 

[Guest Maj Millard]

Using engine type oil in a coolant system of a Rotax would simply be ludicrous !!...............surley they mean Evans waterless coolant !!. Why in the world would you be trying to drop the coolant temperature on a 912 anyway, they run so cool most of the time ! I have trouble keeping my 912 lightwing up in the green arc in the first place, with the standard Rotax recommended coolant/demineralized 50% water combination.

 

To use an engine oil in the coolant system of a Rotax would surley destroy the water-pump and coolant radiator in a short time ,as they simply are not designed for it...............................................Maj...

 

 

[alf jessup]

Maj,

 

I'm sure your correct Evans NPG waterless coolant is what they mean.

 

I'm the same in the trike even with the Evans in it struggles to get to the 90 deg rotax reccomend, it used to be worse with the water and glycol mix.

 

Alf

 

 

[facthunter]

There was a period where KTM and a few others made water pump bodies etc out of almost pure magnesium and some didn't last 12 months. Dissimilar metals are a problem as is air and gases passing into the coolant from seepage of combustion products through porous metals an gasket materials. Use PURE (non ionic) water and the recommended coolant/corrosion inhibitor and change it fairly often.

 

The EVANS stuff may be OK, but I guess it's not cheap.

 

I can't believe that anyone would put Lube oil into a cooling system, either. There was an engine designed by Granville Bradshaw used in motorcycles in the 20's nicknamed the" bradshaw oil boiler", so you can guess how it went. The head was still aircooled. nev

 

 

[JG3]

.....even with the Evans in it struggles to get to the 90 deg rotax reccomend, it used to be worse with the water and glycol mix.

 

For those having concerns about low running temps in the 912, have a look at http://www.stolspeed.com/thermostat-for-912

 

Mine runs about 90 degC all the time now. Simple installation.

 

JG

 

 

[facthunter]

Either that or use a smaller radiator or block some of it off. I do have some concern about the reliability of the average thermostat these days. It is something else to go wrong, but I won't run a car or bike without one. Nev

 

 

[Guest Maj Millard]

The Evans waterless coolant is only one recommended for the Rotax engines. The other is a quality anti-freeze anti-boil mixed 50/50 with demineralized water. I use the Castrol anti-freeze anti-boil exclusivly, and have done so for at least 20 years now with out any drama. It works very well, and contains a small amount of seal lubricant to lubricate internal water-pump seals. This lubricant is exclusive to Castrol.I proved this stuff works in my 582 Drifter over 650 hrs. The water-pump seals in 582 are the achilles heel of those engines, and the seals can go at around 250 hrs. I carried spare seals for 11 years without needing them ! When I sold the aircraft it still had the original water-pump seals in it, and they had never leaked.

 

I have never seen Rotax coolant systems suffer due to 'evaporation'. The 582s will spit a bit of coolant if you don't fit an overflow bottle, but the 912 has one standard and it's simply a preflight item to check the level in the overflow, just as you do with the average auto. More than likely any loss of coolant would be due more to lack of maintenance or servicing by the operator.

 

Alf, trikes tend to run a bit hotter due to less airspeed and less air passing through the radiators. However if you've got the proper coolant as recommended by Rotax, the temps will stay in range at all times and cool down fine after takeoff. That range for a 582 for instance is 60-80C, but most will sit right in the middle at 70 C . I suspect your engine does not have a thermostat fitted as it should have.

 

Bottom line here is we do not need to reinvent the wheel as far as coolant systems go, just follow Rotaxs' service recommendations and you will be fine.......................................Maj...

 

 

[Guest Crezzi]

the Evans waterless coolant is only one recommended for the Rotax engines. The other is a quality anti-freeze anti-boil mixed 50/50 with demineralized water.

With conventional coolant it's also necessary to have water temperature gauge fitted (not required if running Evans)

 

Cheers

 

John

 

 

[fly_tornado]

Either that or use a smaller radiator or block some of it off. I do have some concern about the reliability of the average thermostat these days. It is something else to go wrong, but I won't run a car or bike without one. Nev

The bad old days where the rust got into the thermostat are long gone. You do more damage to the engine when its cold than you would if the thermostat failed.

 

 

[JG3]

[Either that or use a smaller radiator or block some of it off. I do have some concern about the reliability of the average thermostat these days.

 

A thermostat is a lot more dependable than a taped over radiator on a hotter than expected day and the temps are climbing faster than the aircraft...... JG

 

 

[facthunter]

If the thermostat fails closed or nearly so, you ARE going to land. The older ones used alcohol in a bellows. the later ones use wax. I don't find them particularly reliable, and an aeroplane is fundamentally different from a car as you can't pullover to the side of the road and work on it.

 

My preference is for an in flight adjustable blind or shutter (cowl gills/shutters.) This would give less drag as you would only have the minimum airflow through the motor to do the job. You could also close them on descent and stop the engine cooling excessively. Nev

 

 

[Guest Maj Millard]

I'm sorry but I just don't see the problem here. If you use an oil recommended by Rotax, and a coolant recommended by Rotax, and your coolant and oil radiators are exposed to good airflow, you shouldn't have an overheat problem with a 912....am I missing something here ??? I've flown well over a dozen different 912 engines, and some in 40C heat at slow speed in a Storch. I've yet to have one even go close to overheating. I have had my oil temp go up a bit on takeoff in my fully loaded Lightwing, but only because I still had both coolers half blocked off at the end of winter on a hot day. Things certainly stabilize and cool down soon as you get off the power.

 

I block both coolers off 50% in winter because I do early morning takeoffs, and want to warm up quicker. It also helps keep the needle in the green arc when cruising at altitude. Otherwise it definitly would be running way too cold. ..................................................................Maj...

 

 

[samuell]

I had Evans coolant in my old savannah, spent the hole time chasing leaks.It also ran hotter I toke it out and put in 50 50 water glycol mix.Runs cooler and no leaks.