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914 draining coolant and changing coolant lines

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rehn(at)rockisland.com
Guest

Posted: Tue Jun 15, 2021 4:12 pm Post subject: 914 draining coolant and changing coolant lines

Hello All

Iâ€™m due for refreshed coolant lines and of course draining old coolant. 

Itâ€™s been some time since done and at best I remember it was very messy draining the coolant. Was wondering what others have done to minimize the mess?

Any clues and techniques would be much appreciated!

Thanks 

Jerry 

Europa XS 914 Mono



Sent from my iPad

JohnFrance

Joined: 17 Sep 2014
Posts: 78
Location: Grenoble France

Posted: Tue Jun 15, 2021 11:40 pm Post subject: Re: 914 draining coolant and changing coolant lines

Jerry,

Rotax thought about draining the system and included a drain in the coolant pump housing which is very useful.... when the engine is on a bench and the rear of the engine is accessible!



I devised my own method which takes a little more time but avoids the mess. I use a large syringe, the bigger the better and a piece of silicon tubing which I use to empty the expansion tank on top of the engine, I then insert the tube down the coolant return hose 10/15 cm 4/6" and suck it out with the syringe.

Once you have lowered the coolant level below the expansion tank remove the return hose from the tank and insert the tube all the way down to the radiator and empty the system.

A small quantity of coolant remains at the low points of the engine but its manageable with an absorbant rag to catch the drops.



John

_________________
Europa mono Nr 192

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Wed Jun 16, 2021 5:36 am Post subject: 914 draining coolant and changing coolant lines

Jerry,

Like you I use a 1/8inch ID polyurethane hose like our pitot/static lines to push a line down through the spider into the radiator.  Then I siphon the coolant down.  Perhaps there is a cardio vascular surgeon on the site that can make the process easier, as the drain line is like pushing a rope.  Some technique required.



The bad part of this method is you don't flush the system.  Flushing is important they say.  In the past I would pull the coolant line off of the lower #2 cylinder (left front) because it was easy to get to and let it drain.  Later I used a Prestone flush kit and fittings to install an in line plastic elbow in my #2 line and a pressure cap elbow supplied (and modified by grinding and polishing to fit the radiator cap inlet) to allow easy hookups.  That was a bad idea.  Plastic and exhaust pipes don't mix.  



One client siphons down the coolant while the oil is draining.  Then pulls the port radiator hose at the top, puts in an elbow on the hose and a rubber stopper with a hose fitting in the spider 1" hole and  flushes that way.  Of course, there is room on the 914 to pull the hose at the radiator and put in a 90 degree hose, plug the hose and using my Prestone radiator cap elbow from the kit wash water from a hose down through the system and out the radiator.  I did it this way once and it was messy, but it was quick and thorough for a flush.



To flush a nasty system, I still siphon out the coolant, then pull lower #2 hose, hook my flush kit up to the spider/filler neck and flush from the filler neck with my modified Prestone elbow and out my #2 lower hose through the system, with a hose.  Then drain again and fill with distilled water and drain again.  Then fill with coolant.  This is still quite a messy procedure and frankly not a thorough as I like...  So the bottom line is the only time the bottom of the radiator gets a good flush is during a hose change at the 5 year point.



I may die before I finally mod my radiator with a new radiator with a custom drain plug.  That would be the ticket on the XS Europa in my opinion.  But not without its issues as changing one thing on an airplane affects 20 others it seems.



Bud Yerly



--

h&jeuropa

Joined: 07 Nov 2006
Posts: 645

Posted: Wed Jun 16, 2021 9:42 am Post subject: Re: 914 draining coolant and changing coolant lines

Jerry,



As other have suggested, we initially siphoned the fluid.  Last time the rad was out we fitted a drain plug on the port side tank.  Now it's easy to drain.



Jim & Heather

Griffo

Joined: 18 Mar 2021
Posts: 70
Location: The Oaks, NSW, Australia

Posted: Wed Jun 16, 2021 3:30 pm Post subject: Re: 914 draining coolant and changing coolant lines

No experience with a 914 however with my 912ULS:



I do my coolant changes at the 2.5 year mark - so one drain in part of hose replacement



Just remove the lowest coolant hose, followed by the "radiator" cap. It's handy, not essential, to have a second person to hold a wide mouth container up to the open hose.



After bulk of coolant removed, I open one end of each lower hose to remove any "dregs" 



After reattaching all but one hose, I do a compressed air blast into the "spider" tank (cup hand over opening put air gun nozzle between finger/thumb and blast) - usually gets a few more drops.



Drain expansion tank separately.



If using same/compatible coolant, within recommended drain interval, no need to "flush" system.



Be sure to top up using Rotax compatible coolant, mixed with purified water at the 50:50 ratio.



Squeeze/pulsing of the larger radiator hoses may assist in removing trapped  air bubbles.



Conduct brief test flight -  allow system to cool (overnight good) recheck coolant levels & top up.

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rehn(at)rockisland.com
Guest

Posted: Wed Jun 16, 2021 6:18 pm Post subject: 914 draining coolant and changing coolant lines

 	  Quote: 	
		  Thanks everyone, all helped, I managed to pump most of coolant out through the return line at the â€œspiderâ€. 

	
Almost done, have top lines left to do tomorrow. My old silicone lines were all still in good shape and replacing with new silicone.  Glad this is not a project that comes around too often!Thanks again for all the help!

Jerry

Griffo

Joined: 18 Mar 2021
Posts: 70
Location: The Oaks, NSW, Australia

Posted: Thu Jun 17, 2021 7:53 pm Post subject: Re: 914 draining coolant and changing coolant lines

 	  rehn(at)rockisland.com wrote: 	
		   	  Quote: 	
		  Thanks everyone, all helped, I managed to pump most of coolant out through the return line at the â€œspiderâ€. 

	
Almost done, have top lines left to do tomorrow. My old silicone lines were all still in good shape and replacing with new silicone.  Glad this is not a project that comes around too often!Thanks again for all the help!

Jerry 	




It may be  just a little weird but I actually enjoy servicing my engine - the bigger (more complicated) the better.



I dont understand - you pumped out the coolant with the hoses you were going to remove/replace in situ - why?



Just wondering why you go to the additional expense of installing "silicone lines" every 5 years when ordinary high quality rubber  hose would be cheaper and perform the same service (or is this a 914 specific requirement?)

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46

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Sat Jun 19, 2021 1:02 pm Post subject: Re: 914 draining coolant and changing coolant lines

On the topic of hoses.

Gas lines:

Any of the new lined hose that is (R7 or better) EPA compliant seems to outlast the 5 year time frame as a fuel line.  So far at 7 years, with AvGas, my hoses are in superb shape still.  Those using auto fuel with ethanol seem to also hold up well.  And these lined hoses don't stick up the plane.  See the hose manufacturers recommended clamps.



As far as coolant hoses:

Silicone coolant hoses seem to hold up fantastic.  I would consider going no longer than 10 years with silicone personally.  The failure areas of the silicone hoses seem to be the clamping area as they are not as tough without an exterior liner.  Do your research.



The hose clamp area and the type of clamp is always a concern especially with silicone coolant hose.  HPS makes a nice lined hose, but find a 17mm hose size.  A Breeze clamp over tight tears through the hose as the thread cuts in the clamp will tear up hose as will cheap thin clamps.  Lined hose clamps are always better.  These type clamps are still a pain to get off, but they seal better and they help the hose last.  Spring clamps on the coolant hoses when properly sized and fit hold up well with the silicone hoses.  Be careful to use the properly sized clamps.  



Note the rubber coolant hoses hold up well on the top of the engine.  The lower hoses when exposed to reflective heat near the exhaust tend to show heat damage and brittleness if exposed to the exhaust heat.  I'm a fan of using heat reflective sleeve over all the hoses on the bottom of the engine.



Oil Lines:

Pay particular attention to the oil line on the bottom banjo bolt as it can get quite hot and I've seen them get brittle and crumble in only a few years (3 to be exact).  With heat sleeving completely covering the oil line and clamp, they last a bit longer but bear watching.  Do your research on hoses of choice.



Remember, barbed connectors tend to damage the liners of hoses, so if removing a hose that is lined or silicone coolant hoses to facilitate other maintenance, inspect them well for damage after removal.  If they are damaged, of course, replace them.



Just my thoughts.



Bud Yerly

Griffo

Joined: 18 Mar 2021
Posts: 70
Location: The Oaks, NSW, Australia

Posted: Sat Jun 19, 2021 4:09 pm Post subject: Re: 914 draining coolant and changing coolant lines

Great advise Bud - 



I, always "as tight as a bulls arse in the fly season" , have come up with my own heat shielding systems, that actually seem to work, as hoses removed/replaced at 5 years, are still good enough to be recycled for use in ground based equipment. 



Depending on location, I use a combination of malleable builders aluminium "flashing"  or very thin aluminum sheet (scraps of aircraft skin also). For hoses that are exposed to very high heat, I supplemented with exhaust bandage, silicone glued to inside of aluminium. I use safety wire to hold/clamp the insulation in place. 



For over-engine fuel lines - automotive corrugated sleeve, wrapped in air-conditioners reflective foil.



For the most part , the shielding I have made up, can be reused at the 5 year interval.



Oh! and yes I appreciate that the automotive corrugated tubing is flammable and would contribute to an engine  fuel fire.



As far as weight goes - dont know, but would be minimal as shielding only used where hoses may be exposed to significant radiant/convection heat.

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budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Sat Jun 19, 2021 5:13 pm Post subject: 914 draining coolant and changing coolant lines

Griffo,

I still use the red fire sleeve for fuel lines.  I like  Parker / Aeroquip 12 or 10 sized PN FBS2200 fire sleeve.  I prefer Parker Stratoflex as it is more flexible.  Aeroquip is very stiff and is poor for anything under a 2 inch bend radius.  To seal the fuzzy cut ends use either Firewall 2000 or Permatex Red Silicone RTV or it looks like hell .  

Banding if desired is:  10781-4 clamp to secure fire sleeve material over the basic fabricated hose assembly if desired.



For shielding for my coolant tubes and oil lines I use the expensive and somewhat delicate Thermo-Tec sleeving.  For lower engine coolant and oil lines I use: Thermo-Tec Thermo-Sleeve P/N:14015 for 1 to 1.5 inch hoses, and P/N: 14011 for 5/8 to 3/4 “It lasts 5 years but if it gets covered with coolant the darned aluminum reflective material falls off.  Very fire resistant.  Nothing wrong with the corrugated aluminum over the one inch lines, as it holds up and its tough.  



Yea, I know what you mean about the stick on aluminum. I stay away from the aluminized stick on tape because of the fire thing.  Why they have a flammable glue, I don't know why.



I'm not a fan of aluminum flashing because I leave far too much blood and stains on the edges when working on or around the engine.  Of course, I do my trigear behind the gear firewall with .016 stainless, but I rivet or screw it down and use the 3M Firebarrier firewall 2000 sealant.  I really like that stuff.  Try it on holding the aluminum or stainless on.  Works great and not that costly.  Silicone based, so it is fireproof and a "reasonable" glue and better sealant.  I like it for protecting the cowl where the exhaust is just a little too close to the cowl, but not close enough to require a cut and reshape of the cowl.  I use that asbestos aluminum/stainless firewall material.  It is great stuff to experience the "die by a thousand cuts" torture.  My fingers suffer as I can't work the stuff with gloves on.  I trim it so the stainless side folds over the raw edge of asbestos side (or whatever that stuff inside is) and then I just glue it in place with the sealant.  It is like a razor blade though and slow to work with to get it nice and neat.  Really works well for both insulation and fireproofing and I wouldn't do a trigear without it.  I never use it on a mono unless on the cowl which is just a left over scrap from another trigear I finished.  I put a torch to it and I felt nothing on the other side.  



All the best,

Bud Yerly



--

Griffo

Joined: 18 Mar 2021
Posts: 70
Location: The Oaks, NSW, Australia

Posted: Sat Jun 19, 2021 7:56 pm Post subject: Re: 914 draining coolant and changing coolant lines

Bud  - you made me laugh - I have been playing with machinery for 50 years or so and have come to the conclusion - if you dont  donate a bit of blood/skin you havent sacrificed enough to the the job.    



As always, a very informative & thought provoking reply - my thanks

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rlborger(at)mac.com
Guest

Posted: Sun Jun 20, 2021 6:25 am Post subject: 914 draining coolant and changing coolant lines

That is for durn sure!!



 	  Quote: 	
		   On Jun 19, 2021, at 10:56 PM, Griffo <scangriffin(at)bigpond.com.au> wrote:

 

 

 

 Bud  - you made me laugh - I have been playing with machinery for 50 years or so and have come to the conclusion - if you dont  donate a bit of blood/skin you havent sacrificed enough to the the job.    

 

 As always, a very informative & thought provoking reply - my thanks

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